Engine & Exhaust / Q&A

Ask Away! with Jeff Smith: Best Performance Upgrades for a 283 Chevy Small Block Engine


(Image/Trick Flow Specialties)

Here’s a question you probably haven’t got before in your Ask Away! segments. I have a 0.060-over 283 that is now at 292 cubic inches. I just finished the short block and all my friends are telling me to put a big set of heads on this to help it make power. I can get a set of those “camel back” or “double-hump” heads—I think the cast number is 462. This is going to be a very mild 292 in my street rod and I might even add a 2×3 Rochester tri-power setup on it to give it an old time hot rod look. Any ideas?


I have actually played quite a bit with 283 Chevy engines. These are great little small blocks that were small-bore, short-stroke little blocks that seemed like they would run forever. The standard dimensions were 3.875 inch bore with a 3.00-inch stroke.

When Chevrolet needed to come up with a 5.0 liter engine for their jump into Trans Am racing with the Z/28 in 1967, they merely slipped a 283 3.00-inch steel crank in a small-journal 327 4.00-inch bore block and instantly had a 302ci engine.

But I digress.

By increasing the bore 0.060-inch on your 283, you end up with 3.935 inch bore that bumps the displacement to 292ci. The problem with adding bigger fuelie style cylinder heads like the 461 or 462 is that, while these heads increase airflow over a stock 283 head, this also increases the combustion chamber volume.

Those double-hump heads generally have 64cc chambers. The stock 283 used a 58cc chamber. The reason this is important is when we start plugging numbers into a compression ratio program—the short stroke makes adding compression difficult without going to domed pistons.

Since the 283 uses a short 3.00-inch stroke, combustion chamber volume with a flat-top style piston means you really need to make the chamber size very small. For example, a 0.060-over 283 with a 58cc chamber, flat top pistons with four valve reliefs (we’ll call that 6 cc or 1.5cc per relief), a shim steel gasket that’s only 0.018-inch thick, and a deck height with the pistons 0.010-inch below the deck produces 9.6:1 compression.

That’s a great pump gas compression ratio—likely your specs will be slightly different. Most production based small-blocks back in the day were closer to 0.020-inch down in the hole, dropping the compression to 9.3:1. So you can see that even slight changes make a big difference.

Now let’s take that 9.6:1 combination and add bigger 461 heads with a 64cc chamber. That adds 6 ccs, which doesn’t sound like much, but it has a big effect. The compression ratio drops from 9.6:1 with the 58cc chambers to 8.9:1—a loss of almost 0.75:1. That’s huge. These little motors really like compression so with a mild 292 with good compression you might make close to 275 to 280 hp.

Every point of compression is generally accepted to be worth about 3-4 percent power. So if we drop the compression by 0.75-point, let’s call that 3 percent, that’s about 8 hp and perhaps closer to 10 hp. It’s possible that the airflow increase of the larger heads will push the power back up, but the loss of compression will hurt torque throughout the entire rpm range and will also cost mileage—not that you probably care about that.

I’ve never done a straight comparison on the dyno, but I have removed a set of 462 heads from a 287 (0.030-over 283) and installed a set of 520 Power Pak castings that were lightly ported and increased the intake valve size from its tiny 1.72-inch diameter to a 1.84-inch version from a 305 engine. At the drag strip, the car picked up about 4 mph and a couple of tenths of a second. I attribute the better mph to better horsepower mainly from the added compression.

That little engine used an Edelbrock Performer camshaft (204/214 degrees at 0.050 with 0.420/0.443-inch lift) and Edelbrock dual plane intake manifold with a tuned-up Q-jet and it really ran good with a Muncie four-speed and 3.31:1 rear gears. These engines make very little torque, but decent horsepower for their size.

You can still add a set of larger port heads to these engines but you will either need to add domed pistons to improve the compression or mill the heads. Adding better pistons is the one way to go because the rule of thumb is you have to mill the head 0.006-inch to remove 1cc of chamber volume.

So to reduce a 64cc chamber down to 58cc, this is 8cc which means you need to remove 0.048-inch from the head deck surface. This is an excessive amount that will also make bolting the intake manifold on problematic and it’s almost guaranteed that the intake gasket will not seal properly because the angle has changed.

These are the details that few people pay attention to and yet they are critically important. You could take a set of old 58cc iron heads and have them machined to open up the intake valve size from stock 1.72 to 1.84 or even 1.94-inch but then you will also need to pocket port the bowl area to blend the bowl into the larger valve to take cull advantage of this swap. This is a lot of work—I’ve done it before and it will take 8-10 hours of grinding on nasty old iron.

Plus, the heads are almost guaranteed to need new guides, valves, and you will certainly want to add better valve guide seals and pushrod guide plates. By the time you are done with all that, it’s possible to have $800 or perhaps $1,000 invested in a set of ancient iron heads that might then crack. It happens all the time. Remember, these heads are over 50 years old!

World Products makes a 58cc iron head with a larger 170cc intake port and 1.94/1.50-inch valves that would be perfect. It’s not a very popular head so likely you will have to order them and wait a while, but that would be easiest way to update your 283 and not spend a ton of money.

Another approach is Trick Flow’s 175cc aluminum small-block Chevy head for small-block that features the fuelie “double hump” casting mark and would work great on your 292. The heads use a 60cc combustion chamber. Plugged into our compression ratio program, that puts your flat-top 283 at 9.35:1 which is pretty good. This will work well on pump gas.

I would also run long-tube 1 5/8-inch headers in this. If possible, try to avoid the shorty or intermediate length headers as they will hurt the low-speed torque—and with a 292 you need all the torque you can make. Ideally, I would run a set of 1.5-inch headers but these would have to be custom made, yet would really help the low-speed torque with very little loss of top-end horsepower.

As for induction, if you want the look, yes a tri-power setup is nice, but it will cost horsepower compared to even the least expensive dual plane single four-barrel intake. Those old tri-powers look very cool so if power isn’t really an issue then it’s a great idea.

Edelbrock makes a vintage looking tri-power intake manifold that even uses the old stock oil filler tube so you can run old style valve covers with no vents or fittings. The big issue will be finding three old Rochester 2GC carburetors. They are still out there but are becoming harder to find.

We’ve worked with JET Performance on various stories and they do a great job of rebuilding these Rochester 2 barrel carbs, so you might consider them as a source if you find a trio of carbs that can be rebuilt. These engines are becoming harder to find as the last 283s were built for production in 1967.

In the days when a 327 was considered an expensive engine, a favorite upgrade was to bore the 283 out from 3.875 to 4.00 inches and those engines were called 301s until the Z/28 came out in 1967. Then everybody called it a 302. One reason the 302 was rated at 290 hp was it came with 11:1 static compression and 462 “fuelie” heads that were also used on 327 Corvettes and Chevelles.

I have a copy of a set of dyno sheets given to me by Jim Travers and Frank Coon (Traco) showing a Penske 302 engine making 402 hp at 6,800 rpm for the ’67 Trans Am season. It would be fun to recreate that engine with as many close-to-original parts as possible. They were using stock stamped steel rocker arms, a transistorized ignition, and an Engle cam with a single four-barrel dual plane intake. The crossram appeared later.

Hope this will help steer you toward building that little 283 – they are great little engines that will rev to the moon!

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  1. Charles Giles III says:

    Great GM history lesson, i have several 283, 327, 302 DZ engines and internal block parts Nos GM from a COPO Dealership that closed in NC.im
    also sitting on 9sets of small block chevy 49cc cylinder heads from Dart Machinery Inc.Bare heads NOS in boxes.I have built several DZ engines for restorations. The original piston designs are custom made for me with modern technology by Wiseco. cgiles iii

  2. Just wondering how i can ask Jeff about my 84 tbird

  3. Pete Amador says:

    Great article. I currently have a DZ 302 and plan to change the stock iron heads for aluminum 220 AFR heads. Is this a good choice as I want to keep everything else as stock as possible.

    • Tad Wiltman says:

      Very close. I was considering building a 311 small block for autocross and road course use. AFR gave me a recommendation for the 210 competition ported heads. I can’t remember the camshaft rec I got off the top of my head, but was a pretty healthy solid roller.

  4. Jim McKnight says:

    Good article Jeff! Back in the early 90s I put a set of “Double Hump” heads on the 283/292 in my son’s ’66 Nova not thinking about the loss of compression. I also used the 204/214 cam in it and an LT-1 Chevy intake. There was a noticeable lack of torque, but it ran well on the top end. It was still good for 14 flat in the quarter mile. About 2006 we pulled the 283/292 and installed a 406/700R4 combo. The car now runs mid 12s.

  5. Randy Ridley says:

    That was a great read.
    Thanks for taking the time to share your knowledge with us.
    One can never know enough.

  6. I’ve got a couple old 283 not punched yet n set of double jump heads plus easily have access to a 3 deuce set up what kikx if cam would be a good match

    • Need more initial power in the second gear of the two speed powerglide Tran linked up to my 283CI engine four barrel Quadra jet power pack heads The advance is I think 12° with a vacuum and mechanical standard set up. The rear has a 3.21.
      Driving at first warm up more power in second gear after engines warmed up a little bit lower power in second. Hi miles on a no rebuild original Tran. Mechanical advance next to the diaphragm arm seems to be stuck. Distributor is electronic HEI. No points. I know if I had a 3.60 rear that second speed would really power but highway speed would be too much RPMs. Any lower expense options tweaking it without changing heads or adding carburetors I plan not to get headers but I have dual exhaust 1 3/4 “ inch

  7. I have a 283 stamped with the date 7-25-62 on the VIN pad. This doesn’t appear to be a factory stamp, however the factory stamp is upside down? Seems strange. Purchased from a marine shop, I’m thinking possibly was a marine engine? Also has an oil pan I’ve never seen before. It has an inspection cover bolted to the side of the pan. Can this block be bored to 4″ safely? I have small chamber heads and want to stroke this engine with 5/7 rods but not sure what piston to use. I’m wanting to build a ” mighty mouse motor “. I’m going to install it into a Chevy HHR with a 700R4 behind it. Any wisdom from your plethora of knowledge of these mouse motors would be appreciated greatly. Also, any suggestions on a camshaft to use or the best cylinder head to use. I only have the stock heads at this point. I was considering a procharger on it as well. Want to go b@//s to the wall on this as it is going to be the last engine that I build. Definitely likely to be the last Rod build I ever do. Thanks in advance for any information you can share. I don’t want insight to become hindsight.

  8. I’m impressed with the knowledge that you have on the SBC. I would really like to pick your brain about a few things that I may or may not be able to do with my 283. It was built on 7-25-62 or was installed on this date. I believe that it was a marine engine due to where I purchased it from. As far as I can tell it has never been machined before. Any information on the subject would be a great help. These engines are amazing little demons. I have a friend who has one in his 32 Plymouth coupe, and its able to move that heavy old car quick enough to whip almost anything he lined up against. Impressive to me and would not have believed it had I not witnessed it myself.

  9. There’s not really much to tell with the 1962 283 engines. I don’tn have access to any records for marine engines. Assuming this is was originally an automotive engine, all the 283’s listed for use in cars were rated at 170 hp in either full size cars or the Chevy II. In 1962 these 283’s were rated at 170 hp with a 2 bbl but earlier in 1961 in passenger cars these same engines were rated at 230 hp with a four barrel carburetor. The 283 was also used in Corvettes before 1962 – replaced by the 327 in 1962.

    • Rick Flores says:

      283, 2 barrel engines on Chevy ll was rated at 195hp. 4 barrels were rated at 220hp.

    • Jeff, You left the single biggest impression on me while you were the editor of Car Craft magazine. “Car Crafting should be a pleasure, not a pain” Ever since reading that article, I have always enjoyed the hobby as safely as possible. Alot fewer scars and alot of happy years working that way! THANKS!

  10. have a set of double hump heads, they have been worked but don’t know about being serviced ground on block side, any way to get a measurement on thickness for them.

  11. Scottie sparks says:

    I would like to get advice ASAP before I lose my mind:

    2013 5.3 afm with vvt

    Had engine built took out afm lifters and builder used mc1390 cam.

    Had ecm flashed to delete afm

    Getting multiple misfire 1,4,6,7 and rough idle and all stabil tract and engine lights flash at idle or park speed.

    Under acceleration it runs like a dream and lights go off

  12. Great info as I am going to build one of these little motors.We ran a .125 over 283 back in the day when we raced dirt track and it was a tough engine.Thanks for the info and I hope to add a 671 blower when it’s done.

  13. Can you mate a th250 trans to a 283 without any hassle?

  14. Jeff- great article. Im in the process of researching a 283 build and wanted to double check the info above. As I understand it, The Trick Flow DHC 175 head will only work if you punch the bore to 4″. This is due to the 202/160 valves. Im checking with Trick Flow to see if they have an option for 194/150 valve.

  15. john nasmith says:

    I bolted on a set of 1988 corvette aluminum heads onto my
    283 engine. The heads were $550.at the daytona chev dealer.
    Great little engine. the heads just bolt on- no mods- -1.94
    intake valve- 58cc chamber- compression comes out about 9.3.
    Sweet! I’m biulding another one now.
    I don’t know anyone else who has done this. Why not?

  16. how can I eliminate the oil bath and internal baffle 283 like to put 4 barrel on has 2 barrel now

  17. how can I eliminate the oil bath and internal baffel 283

    • Jeff Smith says:

      This is really easy Derek. The internal baffel inside the lifter valley was there to pull out liquid oil before ducting the crankcase pressure into the road draft tube. Assuming you will use later model PCV valve with this engine, remove the baffle and then drive in a freeze plug into the hole at the rear of the block for the road draft tube. If you are talking about the oil bath air cleaner – by all means get rid of that and use a paper air filter assembly- they are far better. The best way to keep oil clean is to use a really good air filter.
      For an intake manifold, any dual plane small-block will work as long as it has the traditional bolt pattern. Watch out for later intakes after 1987 that used a differnet intake bolt pattern with teh center four bolt holes. Any traditional small-block Chevy intake will bolt right on to your 283.

  18. Dax McCombs says:

    I’ve got a .040 over 283 in my 57 Chevy. It has a set of factory stock 302 pistons I turned down to fit and a set of the World Products S/R Torquer heads you mentioned in the article with an old Isky 505C reverse rotation gear drive roller cam specs are 505 lift 330 advertised duration. 4-speed 614 gear. Just a want to do project it sees 8500 rpm quite regular. Don’t have a ET on it but it is a blast to drive!

  19. Just wondering how a set of factory aluminum ZZ crate engine heads would work on this flat top 283 combo. I believe they are 58cc also, but not known for good flow on a 350. Also, are tri-y headers a better choice on this combo than long tube? Thanks for your time.

    • Jeff Smith says:

      I ran this through my compression ratio program. With a 58cc chamber, flat top pistons with four valve reliefs at 6cc total, and the piston 0.020-inch below the deck and a0.039-inch head gasket, it would 8.8:1 compression. That piston is pretty far down in the hole and creates a nearly 0.060-inch piston-head clearance which is too much.If you deck the block to give 0.005-inch, the compression jumps to 9.1:1 which is better. Or, if the engine is already together and the piston is 0.020-inch in the hole, you could go to a Fel-Pro PN 1094 rubber-coated steel head gasket that is only 0.015-inch thick. That would produce a 9.31:1 whic his close to ideal.

    • Bart Logan says:

      Also, IIRC the ZZ350/ZZ4 uses a Vortec cylinder head so bear that in mind when choosing your intake manifold (and valve covers).

  20. Fred Mueller says:

    I replaced the rocker stud with a threaded stud and now the nut runs out of room before it hits the push rod, have any idea how to fix it?

  21. Gene Davis says:

    Jeff… Were any parts of the 350 ci and the 283 ci engines used in making the 305 ci engine? What is the difference between the 302 and the 305 engines?

  22. I know this is an old blog but I would like to know what kind of power everyone thinks this setup will produce because the Dyno software I have is giving an unbelievable answer and I have checked to make sure I have everything plugged in correctly. So here is the setup: 283 bored 0.03, 327/3.25 stroke crank, aftermarket 307, 0.030 flat top pistons with 4 valve reliefs 6c total volume, vortec 062 heads with stock valves, stock 1966 chevyII 283 cam that I have used a degree wheel on to find it has seat to seat duration of 300 degrees and .05 lift at 250 degrees, and this is the original stock cam has GM casting number and all on it. Total Lift is only 0.398 and a lobe separation of 114, can even give the open close degrees if necessary OEM part number is 3732798

  23. Addition info the block will essentially be a 0.030 over 307 making a 311, has been decked to keep the .02 clearance, heads are stock 64 cc with stock rockers, Edelbrock 2116 vortec intake 600 cfm carb a 0.018 shim head gasket, specs on cam are intake O@32.5 BTC, C@87.5 ABC, exhaust O@74.5 BBC, C@45.5 ATC, 78 degree of valve overlap, these are at seat to seat
    Intake O@12.5 BTC, C@57.5 ABC, exhaust O@54.5 BBC, C@54.5 ATC, these are at 250 degree @ 0.05 lift
    anyone with a Dyno program let me know what you come up with for HP

  24. Jeff, enjoyed the read and very informative. Just to let you know trick flow now makes a cylinder head for 283 and 327 that have 56 cc chambers ans 194 and 150 int. and exh. valves! These should plug into your formula very nice. $ 590 each from summit and all set up for roller rockers and guide plates. Max valve lift .540 in. Check them out, TFS 30310002. Love to see what they would do on a dyno test, Pat

  25. The big qualifier for boring a block is core shift. Thin wall casting was in its infancy in the 50,s so extra meat was left in to allow for core shift. Look at the casting around the front cam bearing. If it is well centered, then the block is a good candidate for a large over bore. Nowadays we can have it sonic checked, but in the old days they would do the ruff cut then sound the bores with a small ball peen hammer before spending the time on the finish bore. Crude but 99 percent of the time successful!

  26. James Register says:

    I can’t find after market pistons .030 over. I had a friend who told me of a website,but he passed away and can’t remember the site, so if someone would help me I would greatly appreciate it. I need pistons other than cast. So I can get my blocks machined for these. I need to bore at least .030 to clean them up. I want to get these great engines back on the road.

  27. Hi Jeff, fantastic amount of tech detail in you initial reply.
    I too am building a 283 (292), i have the powerpack heads which i machined for 1.94 int valves, i got a bit carried away porting them and ended up with 64cc chambers, what do you think would happen if i stuck with the stock cam (very low overlap) used 1.6 rockers and 9 lbs of boost from a sc blow through setup with a modified Keith Dorton 500cfm 2300 2bbl to compensate for the low comp ratio ?
    Kind regards, Jim.
    Nottingham England.

  28. Gene johnson says:

    HI Jeff, I love to read about the old 283. I am fixing to restore my Dad’s old 66 C10 he left me back in 75. It still has the original 283 in it. I rebuilt it in 79 took it 30 over and the stainless steel crank 10 10. And a stock spec cam. I messed up and used Fel-Pro head gaskets on it and shortly there after blew one over to a water jacket. I recently looked at the certified net horsepower tag and it shows it at 4200 RPM it says 145 HP. When I rebuilt it I went back with a number 2 GM intake and a Carter AVS 4 barrel and a 75 HEI ignition and some High Rev lifters and valve springs. I quickly learned that little 283 would sling a mechanical pump off in a heartbeat. Was the factory shim Steel head gasket a 10 or 15 thousands of an inch ? Thought I might go ahead and freshen the motor back up since it has about 45,000 miles on it.

  29. Just stumbled onto this thread. Have a question heard that the early 283 blocks had more meat on them making them better candidates for .060 over. Is this a fact or bologna?

  30. Hello Jeff,

    Very informative. Thank you! I do have a question…..I am a little confused about what the stroke is on a 283 overbored 0.030 to 3.905 using a 327 SJ crankshaft and 307 +.0.030 pistons. When I plug in the numbers you mention in Summit Racing’s Compression Calculator I can only arrive at the same CR’s if I use a 3.00 stroke. Isn’t it actually a 3.25 stroke? The CR increases substantially.

    Thanks for your time and consideration!

  31. Can i put those heads on a 267

  32. Jamerson R Franklin says:

    I have an in line dual edlebrock carb set up that I want to run on my 283. My 283 has been bored .030 over and have single valve relief pistons. I am using the original 283 stock heads. Is this a good combination or will it cause me to lose bottom end torque?

  33. I keep reading where people used to bore the early 283s 0.125. . I want to do this. but can’t find the pistons for the life of me. I appreciate it if anyone can help me out with a supplier. Thank you!

    • Randy
      The answer is simple – if you add 0.125 to 3.875 you get 4.00 inches – this is the same bore and stroke combination as a 302 small-block Chevy. So look for a 4.00-inch bore with a 3.00 inche stroke piston. Then al lyou ahve to decide is what rod length you want. I’d suggest a 6.0-inch rod whic hwill make the piston lighter, but a 5.7 rod combo is the stock Chevy 302 combo.

  34. On a 1967 283 motor where does pivot ball connect to the clutch pedal or zbar

  35. Greg Burns says:

    Thanks Jeff
    Great article on the 283!I am building a 60 over 283 with 12.5 compression and floating pins very excited to see how it performs

  36. John Loftin says:

    Hello Jeff, I’ve got a 283 I’m building, 0.030 over makes 3.905 bore, using stock steel crank 5.70 rods, flat top pistons, stock cast heads ported but taking the same valves, 1.72/ 1.50 with Erson cam 288 duration, .432 lift , 111- 115 lobe separation. Will this give me good tourqe , or should I go with a bit more lift cam, oh, and going with dual plane performer intake manifold and 650 Holley

  37. John,
    Right off the top – making torque with a 283 is difficult in any situation because the engine is so small. But that cam choice is waaaay too big for a street 287ci motor with a 3.00 inch stroke if you want to make useable torque. That cam will put the torque peak at around 5000 rpm – which is way too high. I looked up the line of Xtreme Energy Comp flat tappet cams and you can get a 212/216 degrees at 0.050 Xtreme Energy cam XE256 with 0.447/0.454 lift which is more lift and less advertised duration at 256 degrees. This is a much better move for a street driven 287 with stock heads. This shorter cam will bring the peak torque rpm point down to a more reasonable 4,000 rpm or so and low-speed throttle response will be much better.

  38. Where to get info on how to tell if it is a 283 engine every one leaves stories just need where to get numbers on engine

  39. Chuck Applegate says:

    I think your math is off ……….64cc minus 58cc is 6cc……..not the 8cc you stated.

  40. What year did they make the Chevy 283.

    Thank you

    George savage

  41. John Heffner says:

    Hello I have a 1983 S-10 pickup Durango longbed and I’m putting a 283 in it I’m won’t besides the 700R4 transmission what else would be a good trans for my 283

  42. this is great talk for a new builder. yes I played WITH THE 283 too. Stuffed one in an Austin Healy 100, and another in my ’56 4 dr hardtop belair. Now I’m up to the biggest small block. got double humps for it. still noodling on cam and pistons. Any help is appreciated. I wish I had the compression ration program Jeff does to size the pistons in my 400 small block.

  43. Doug Wilson says:

    Great tech review on 283s. Good note on chamber size, and valve dia. A neat old racer trick was to roll back the cylinder wall at top, only by the intake valves to aid air flow with 1.94 in valves. 283s run so smooth as well….best attribute.
    Going to take a look at a set of TFS 170s…sounds like the ticket. I have acquired 5x 283s over the years from 61 to 67 blocks. 2x had sj 302 steel cranks for racing. Also, Heavy blocks when compared to a 350. If you want to build higher compr, ..look for the corvette style L2148,L2149 TRWs. There out there, and are made left and rights due to offset wrist pins. This dome us lower and flatter than a 302 style.

  44. I have a ’61 Bel Air running its stock 283 170bhp and iron ‘glide, 3:08 diff. I have a spare ’68 stock 4bbl manifold and Q-jet: is this a useful swap? I would need to remove the road draft system as you described, but I seem to remember the Q-jet uses a bigger-bore fuel line and possibly a different fuel pump? A factory 2″ dual exhaust is going on using stock rams horns and a spacer to replace the butterfly valve there.

  45. hi Jeff, im interested to know if there a way gaining some horespower from a Monza 262.. can 283 heads fit? , or is there comp ratio drop? has there been any builders of these changing to go fast motors? many thanks Al from NZ

  46. Just came across this and i would like to know few things if you have the time to respond.
    i have a 283 chevy and i want to replace all internal parts only(pistons rings rods valves cam lifters manifold carb etc etc) and beef it up to appr. 300hp.
    will be using this daily in summer NO RACING.What should i be buying to make this happen.

    Thank you for your time.

  47. Craig A Emping says:

    I had a 283 engine in a 57 Chevy duntov cam shaved heads with a Holley 4-barrel in a Muncie 4-speed it was a great car this is really needed a lower rear end lower gear but did not have the money at the time to do that was in high school then

  48. Jeffrey Anderson says:

    Has anyone used Schneider’s 135H cam in their 283? The cam has 218 I/E duration @ .050, .460 I/E lift, and 110 LSA. 305 416 heads, milled .030, EDL Performer,and Summit 600 cfm. 3.50 gears behind M20 4-speed.

  49. Hi Jeff,

    I have a very stock, low mile 57 Bel Air that has two modifications (I purchased it this way), 57 Corvette Dual Quads & the Iron Powerglide has been swapped out for a Tremec 5 Speed. Engine was a 220hp power pak originally. Wanted to put a Duntov Cam in it, however I was wondering if the 220hp power pak pistons would be a problem due to lack of valve reliefs? Wanted to use the Duntov Cam, recurve the distributor, run 2.5″ Rams Horn Manifolds & Exhaust. I’m guessing I should also install World Products 58cc heads or Trick Flow DHC 175s with1.94 intakes.

    The problem becomes where to stop as I don’t want to rebuild the whole engine, just really find out if the Duntov Cam will go right in and drive the car. I afraid to create another unfinished project. Thanks for your insight & expertise, Thanks, Al

  50. Bob Donath jr says:

    I have what I believe is a 283 engine that the freeze out plugs are different size on each side. The bigger ones are put in back words from the rest of them. Can someone tell me what I have hear.

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