News & Car Culture / Top 10 Engines

Top 10 Engines of All Time (#6): Chrysler 225 Slant Six

Editor’s Note: This series counts down the Top 10 engines of all time—see how the voting was done by reading our initial post.

Chrysler 225 Slant Six engine

In a hot rodding world dominated by V8s, many of you decided to think outside the V…er, box.

At #6 on your Top 10 engines list, you’ll find the first gasoline-based inline engine of the group: the Chrysler 225 Slant Six. While it doesn’t possess the cylinders or overall displacement of the other engines, the Chrysler 225 Slant Six makes up for it by delivering gobs of torque and a cockroach-like lifespan.

You just can’t kill ’em!


First produced in 1960, the Chrysler 225 Slant Six replaced Mopar’s old Flathead-style engine.

The inline engine was given the Slant Six name because of its unique, 30-degree tilt toward the passenger side of the vehicle. This design was implemented for several reasons, according to Chrysler’s original 1960 press release:

  • The center of gravity is much lower than in upright engines
  • Increased clearance for use with the Plymouth Valiant’s low-profile hood
  • Engine accessories are more accessible

The “slanted” design also allowed for the use of equal-length intake runners and header primaries. The result was improved distribution of the intake air charge and reduced airflow restriction. Combined with a unique internal cylinder design, which featured a much smaller bore than stroke, the improved airflow helped the 225 Slant Six deliver tons of torque. And when the engine’s original one-barrel carb was dumped in favor of a two-barrel carburetor (a common practice among hot rodders), the engine offered even more performance potential.

From 1960-62, Chrysler also offered a Hyper-Pak package, which included a four-barrel carburetor and numerous performance upgrades. This parts combination helped push the Chrysler 225 Slant Six’s power output to almost 200 horsepower—almost V8 range!

Still, the Chrysler 225 Slant Six became most-known for its durability during its 23-year run from 1960-83—as your fellow gearheads pointed out…

Reader Quotes

“Slant Six 225! Bulletproof! –Chris L.

“Not a Mopar guy, but I have never seen anything tougher than a Slant 6 Chrysler!”–Leonard A.

“The Chrysler 225 ci Slant 6—reasonable on fuel, never stops running or wears out, and has loads of torque. My mum had one with over 300,000 miles and it never even had the tappet cover off once!” –Jeff N.

Fun Fact

The Chrysler 225 Slant Six was not only used in cars and trucks, it also provided power for farm tractors, forklifts, and boats.


The original Chrysler 225 Slant Six produced around 145 horsepower at 4,000 rpm and 215 ft.-lbs. of torque at 2,800 rpm.

Aftermarket Upgrades: Six for the Six

Because of the durability of the 225 Slant Six, aftermarket manufacturers continue to offer upgrades and replacement/maintenance parts. According to Summit Racing, six of the more popular parts include:

Editor’s Note: This series counts down the Top 10 engines of all time—see how the voting was done by reading our initial post.

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  1. Graham Kluver (Brisbane Australia) says:

    I have had a 65 AP6 Valiant 225 slant since new (Nov 65). After more than 48 years and over 880,000 KMS on the same engine (same crank, cam,rods and pistons) finally needed an engine rebuild. Still started easily and had plenty of power, but plugs tended to oil up. Had replaced valve seals on two occasions during life time. 30 thou wear in bore and less that 10 thou on crank. Now running it it again. Truly remarkably tough and confirms comments made by others.

  2. Fred Armentrout says:

    I had a 1979 Plymouth Volare 225 slant 6 that was incredibly durable. The car fell apart while the engine still hummed like new!

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  4. Erm…I killed mine.

      • Mike J. Sittnick says:

        I killed two. First one had an oil leak and I never added the oil (my fault). The second one had an oil pump weakness, the engine got hot and caught fire. Block broke (also my fault). In both cases the engines were 25-40 years old.

        • Mike J. Sittnick says:

          I should point out that I have owned numerous Darts, and the engiones lasted fine on most of them (I killed one ’66 and one ’73), replaced the ’73 with a ’71 engine that went to the end (needed lower profile oil pan), a couple of ’74s, a ’66 that slid on ice into a police Crown Vic (Crown Vic won, engine still ran though), a ’77, and a ’68 dying from rust or were sold off.

  5. Just bought a 63 Valiant 200 Signet with a slant 6. Im not a mechanic or gear head. Excited to hear the history of this engine is so strong. 58k miles on my purchase. Sounds like I may be driving it awhile!

    • A good upgrade is the cable throttle linkage from V-8 Valiants. Installs with its metal plate screwed to the firewall in place of the existing plate. Later intakes, 1 and 2 barrel, are already made to accept the cable linkage. Aftermarket 4 barrel setups work horribly poor using the existing linkage with its twisting butterflies. Can be done but I hated it with a passion.

    • Brett – I have been a Mopar/Slant six fan since 1963. Check this out:

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  7. dave meinhardt says:

    Had a 72 Gold Duster and a 70 Scamp- After sitting outside in -20 weather (no garage) it would start no problem when the Brand New Caddy down the street wouldn’t start. Anyone remember that clasic Mopar starter sound? The engine wasn’t too fussy about being super finely tuned, had decent pick up and gas mileage. As a kid a saw a guy who made a v-8 out of two Kawasaki 1000cc motorcycle engines for use in his midget racer. I wonder if you could make a V-12 out of two slant 6’s lol

  8. I have a 69 Valiant slant six 225 that has been sitting for 23 years. My mother was original owner. My daughter and I will be restoring it in the near future. Can’t wait to drive it again

    • Bill OBeirne says:

      Saw your comment on 10 best engines. I too, found a 1972 Valiant in a Garage which it had sat in for 24 years. Driving now, and have put on 10,ooo miles since purchase in November 2015. Fixing the little things and enjoying it a bunch.–Bill

  9. the low hood line of the 1960 Plymouth Valiant is erroneous; in 1960 the Valiant was introduced as a separate line and not a model of the Plymouth line. In 1961 it became a Plymouth. Typical MoPar badging. In 1962 the Desoto was dropped as a nameplate; it lived on as a new model Dodge, the 880, which looked like the classic and currently continued Chrysler much more than the all new Dodge 330/Polara. The 1961 Dodge Dart was a full size car, then the name Dart was dropped, then revived in 1963 as a rebadged Dodge Lancer.

  10. As far as the production run of the slant 6 is concerned, they were used in pickups until 1987, when the v-6 came out. My first truck was an ’84 D-100 with a “leaning tower of power” and a four speed manual. Frame rotted through but still even had the original clutch. Biggest repair I ever made was a rebuilt carburetor and a new fuel pump.

  11. Just bought a Plymouth Volare Wagon with a Slant Six. Put some new plugs and wires on her she she purrs like a kitten. Absolutely shocked at how nice the car runs.

    • my parents had an ol s\6 volare wagon lol…. fond memories of that ol car. would be interested in buying if ur interested in selling.

  12. gene martin says:

    One of the greatest engines ever built. a true shame that Chrysler will not bring it back. re done with EFI and high energy ignition it would meet all smog tests and run forever. Are you listening Chrysler?

    • A-men I have a 1980 dodge 2door diplomate only 62,000ths miles onthe225 engine given to myself by #1 owner great car chrysler should do better.

  13. Ossi Keitaanranta says:

    Have this in my 1966 Dodge coronet, works fine and fuel saver too.

  14. why are superchargers so trash

  15. I killed the engine and not the car. started it up in a blizzard pulled out didn’t let it get warm and 6 miles later blue and purple smoke filled the car. 59.995 miles on engine. called my dad… he came and got me drove the car 26 miles home and the engine locked up. 🙁 My mom’s 1972 duster bit the dust. because of my stupidity.

  16. Carl St.clair says:

    I had the 225 Slant Six in my 1976 Dodge Aspen 4 door sedan It was one of the best engines I had ever seen as it outlasted the body at that time I bought the car in 1981 it had 120,000 miles on it and my complaint was they should have built a better body.

  17. Amirmahmood shasti says:

    Yesterday i bought a 1974 duster, in first day after running about two hour engine fell apart and connecting rod cracked and bearing moved, and block damaged and cracked …its a record as i think

  18. Ha d a 61 Valiant V20 tradede in on a 69 Charger RT Boy do I wish I had both

  19. As a Dodge store employee most of us would put our teenagers in something with a slant 6.
    We use to say with a slant 6 that oil and coolant was optional !

  20. Have used my 1987 W100 225/4 spd ” Dodger1 ” for hunting/fishing for 25 years… ” Creepy_Crawler_Mode ” good ‘ol 4 low… this truck will not stall no matter how steep the hill, without tending the gas pedal, the slant 6 stroke is soooo long! Pulled out more dead/stuck trucks/cars/quads than you can shake a stick at… drove over trees, through rivers, piled game in the back… finally last year the clutch disk cracked/separated… apart now, up on blocks, having a bit of trouble finding a clutch… sad to see My_Dodger1 like that… Yeseree, it’s all about forcing you to buy new these days… I’m sure if Dodge did bring the slant 6 back, it would be so over engineered you probably wouldn’t even be able to see it… 😉

  21. We had hundreds of them in Dodge SixPass pickups in the USAF….and they were unbreakable. Cruised at 90 mph on the Autobahn for hours on end. Smooth, too.

  22. But with no mention of the Buick V-6, the list is questionable. Over 25 million were built!

  23. I had a 73 Dart Sport with a slant 6. Threw a rod less than 100K.

  24. Christopher McCarthy says:

    I have bought a 1964 Plymouth Valiant 200 with the super six 225ci. When I started out as a mechanic the first tune up I did was on this same model year and the first motor I rebuilt was also a 225 slant six. 52 yrs later and this car I found in a scrap yard is also most ready to fire up. My hope is that the cold compression I found to be still in tolerance will be even better after it warms up. When I found it it only had 80,000 miles on it and had not been driven since 1980. The mice had taken up home keeping and the fuel is bad. I also had to hammer out the oil pan that was full of sludge. But after close inspection the bearing look still in good shape the cam has very little ware, and the cylinders have no scoring so with luck after I plastic gauge them and re-torque them, rebuild the carb and she should fire right up for my first road test. Replacement parts are hard to come by and I have rework what I have but it nothing I’m not used to after being in the Army for almost 18yrs. It makes me feel like that kid just starting out again.

  25. I’ve owned 4 slant sixes, still drive one to this day. When I was a teen, our “handme down” car was a ’66 dart 4dr with a 225. It lasted through my mom, and then 3 teen agers. They are superbly tough, overdesigned is what my dad always said, and he was a mopar mechanic for 40 years. When they quit making them, he was upset. He liked the power of the new v6s when they came out, but he knew those would never last as long as the old leaning tower of power. He had a saying “when it starts ticking, you should probably put a couple quarts of oil in it, or a gallon of water”. That was the honest to god truth.

    • Oh forgot to mention, the combined total of miles on those 4 slant sixes I’ve owned, would be slightly more than 3/4 of a million miles. That’s low because my current has less than 100k on it, and I don’t drive as much anymore. Avg. economy was around 17 honest mpg(city/hwy combined) for all of those(2 were trucks). Yearly maintenance was less than $50 a piece. Even my current one.
      You basically just got tired of driving the damn things and gave them to someone elses kid for a couple bucks, or someone Tbones you and totals them out.

  26. What a great engine,the 225 slant six.I bought the Valiant Safari Stationwagon in 2006 and drove it on until one cylinder began to give problems but it still worked tirelessly.I had the whole engine redone in 2015 and have just done less than 2000 km since.I look foward to pull this great car to Limpopo (RSA) in June(2017).I love the power and smoothness of this car.

  27. I had a ’66 Dodge Dart w/ a 225 slant six and a 727 Torqueflite transmission. That combination was Chrysler’s one-time claim to fame for building quality machines, a reputation long gone with the junk they’ve make recently. The 727 Torqueflite was as “bulletproof” as was the slant six. I also later had a ’73 Dodge D100 pickup truck w/ a 225 and a manual transmission. I wish I still had it instead of the miserable ’07 Dodge Dakota 3.7 L six that I own and hate today.

  28. David M Norris says:

    I had a slant-6 for 14 years and 168,000 miles. The car rotted but the engine was always solid

  29. Tom Andtews says:

    I owned a 1979 dodge Aspen bought brand new in the middle of the might be going out of business days, and it was a great car. It was a two door sport model with a 225 super six engine. There was no blind spot in the rearview, and it was a really good looking car. I got it for a song. The fools at brake check did a brake job . On the way home after leaving the shop my brakes failed and the best car I’ve ever had got totaled. She was silver and black with a rear spoiler I ordered. Damn fine car. I sure don’t know why Chrysler won’t bring it back after the success of the 4 liter AMC fuel injected straight six engine. That could be the shot in the arm Mopar is looking for. Just saying.

  30. Brian Eastman says:

    I love the 2 barrel carburetor in the SUPER Slant 6 cylinder engine in a 1976 Plymouth Fury salon 4 door.

  31. betty murray says:

    my work truck was a 1983 ram 1500 slant six 727 torqflight.drove it 17 years everyday.very little maintance.

  32. I had an 80 Aspen wagon and couldn’t wait to get rid of it as it couldn’t get out of it’s own way.

  33. James Kingston says:

    Have the slant six in my RHD Barracuda 1966 great car.

  34. I have a barn find 40000 mile original 68 Plymouth Valiant Signet with the Super 225 Slant Six, what a smooth running motor at 50 years

  35. Brandon Heisler says:

    I have an 81 Dodge Ram d250 3/4 ton pick up it’s white and it’s got a 225 slant 6 single barrel carb four on the floor and it only has 26,045 original miles on it my grandfather bought it new back in 1981 with a thousand miles on it and he drove it back and forth to work for 11 years and then used it to haul water for the garden and salt for the road and it still looks great he passed away 5 years ago and my aunt said that she is going to scrap it and I told her know that I want the truck I’ll give you $500 for it and bought the truck put a starter solenoid in and a new battery and it started up with 5 year old gas and now with a few maintenance things done it purrs and runs like new

  36. Brandon Heisler says:

    By the way if you guys want to check out the truck go on YouTube and search Mopar man and is a white 81 Dodge Ram you’ll see a picture of me sitting in the truck

  37. gregory g nasralla says:

    My first car was a 1965 Dodge coronet sedan that I bought in 1969 and it had the 225 slant 6. Loved it.

  38. I had three 225’s 1974 Dart 4 door, 1973 Demon, 1973 Valiant they were all easy to maintain and just two weeks ago I was driving an old country road and what did I find 1968 Dart 4 door for sale cancelled my flight home and drove home 1400 miles and not a hitch (90000 miles on it now) just broke in these are great cars.

  39. gene martin says:

    I raced a 225 slant six at a small dirt track in south alabama for a couple of seasons. The locals still talk about that little blue dodge dart that could outrun those chevy v8’s. the local track changed the rules that allowed sixes to run virtually unlimited against stock v8’s. there were a couple of 250-292 chevies, a 300 ford, an OHC pontiac and my slant six. The v8’s could not keep up. I bored the block .060, ported and polished the head, cut the head .060, installed bigger valves, had a custom Kay Sissell cam ground,bigger valve springs, titanium valve retainers, installed a set of Jahns 12:1 pistons, an offy intake with a 500cfm two barrel(rule max allowed) and custom headers. That 4 1/4 inch stroke came off the corners like a rocket ship and sounded like a homelite chain saw on steroids. I did not win every week but I never finished out of the top 5.the track abolished the sixes after a couple of seasons. seemed like the v8’s had had enough. I built several cars after that and went on to run short tracks around the south but NEVER…..EVER…had more fun than I did with that slant six.

  40. Frank Furtaw says:

    I have a 1962 Dodge Dart police cruiser. ran it for show and parades for several years…finally bit the dust…anyone know where i can get a replacement engine? I live in central calif.

  41. I loved my 225 in my 75 D100 with a three on the tree. When it got rearended and shot the engine out the front! Only to have the engine continue to run through it all. I rebuilt it later, only to sell it because the body fell apart. To this day I love that engine. It’s True oil and water was always only an option. I never had any trouble with this awsome motor.

  42. I have a 65′ valiant with a super 225 3.7 in it. It had 56,000 miles on it and it’d say for ten years when I got it. I have over time finally got her running. Still with the single barrel carb. No upgrades. But I’m female. No willing mechanic to keep her up. But I’ve ran up 800 back fees on it. I’m scared to get it impounded. But long story short I put it up for $2000 and after they find out the back fees only offer me $1500. Anyway after reading this blog , I figure best to keep it. Cuz I know I’m gonna hate myself for getting rid of her even if I got 2ooo cuz honestly I luv that car and she’s so cute. But boy I wish I had a willing soul who would help me with her. But question is , $2000 is stilltoo little of a price to sell her for ain’t it. And if it is what do u think it should go for .? And if anyone is near Lodi California, possibly would u like to help me with her. ?

  43. My first car – 1962 Plymouth Valiant with slant 6 and 3 speed on the column. Loved that car, sleek lines, and lots of torque.

  44. Giulio Zucconi says:

    Iam presently 61 years old. I have been working on cars since my teenage years and still work as a mechanic or as they say today an auto tech. Back in the day I owned a Duster with a 225 slant 6. It was a very durable eng.I use to work on lots of them , not much use to go wrong with them but I use to replace the ignition points (not many techs even know what points are today) lol and replace fuel and air filters , spark plugs pcv and that sort of thing, Not much went wrong with these eng. The one defect that the slant 6 had was that the fuel pumps would leak oil and the oil wound eat disinergrate the motor mount that sat below the pump as a result of this I replaced my share of fuel pumps and mounts.The way I remembered the firing order was 15/too young 36/too old 24 just right. I would buy 1 in a heartbeat if 1 would come my way.

  45. When I was 18, living on my own, my father picked up a 72 four door dart with a bad engine. Picked up a junkyard slant six and with the help of a tree and a come a long I put the engine in. That was the best damn car I ever owned. One morning I got up at 6am to go to work and it was 48 below zero and I never thought that car would start. It cranked ever so slow: I just kept pumping her and it fired once and that was enough to get the old girl going. All of the belts squeeled until everything broke free and that old girl never let me down. That was 35 years ago. The only thing that will kill any engine is not changing the oil. I ended up putting a 2 barrel intake and carb on her and she ran even harder!

  46. ed Teubert lll says:

    l enjoyed all of the stories
    l have a slant 6 in a massey
    my question is did they make a slant 6 industrial engine that was bigger than a 225???

  47. My grandfather bought a 1976 Dodge van with a slant 6 (225). That engine survived the body NO PROBLEM. We replaced the timing chain once, but that was it. The van had the floor boards completely rusted through in the front, …to the point I was terrified to even sit in the seat without ending-up with my butt on the street! 🙂 The body was AWFUL… rusted through in SO many places (before adequate rust-proofing, obviously). He finally “traded it in” (LOL!) for $100 for a newer van. Grandpa lived in Michigan, having to survive with salted roads, etc. To say the least, HE GOT HIS MONEY’S WORTH out of it! LOL! Had the floor boards not rusted completely through (could’ve done a bona fide Flintstone’s stop! LOL!), he would’ve probably kept it a lot longer!!! The slant 6 was great! The alignment of the engine with the rest of the drive train was, TO BE SURE, a little askew! It required NO FEWER than 17 universal joints. (NOT KIDDING!) My grandfather took my brother and me ALL OVER Michigan – and Canada – in that van. He bought it “stock” with NOTHING inside save the front seats. Decked it out with a full sized (sideways) bed on a plywood platform, with storage underneath for luggage or whatever. Assembled a make-shift closet right behind the driver’s seat. Fashioned an outlet for a TV opposite it to go behind the passenger seat for a TV and/or small refrigerator, coffee maker, etc. Went all over the USA in it with my grandmother, staying in KOA and other type parks.

  48. PAUL KNISELY says:


    STATE $$$$ REQUIREMENTS. 425806520NINE

  49. In the summer of 1980 I saved enough to buy a 1972 Dodge Dart for $950. It had 95,000 miles on it and I was terrified it wouldn’t last. Lucky for me it did. There was a thing called the Dodge Dart fan club whose president called me nearly 10 years later when I sold the car for $250 to ask if I had any “Dart stories”. I had two. One was that the Dart began to lose power over time and one day just barely made it over the hill to where I lived and I assumed that its time had finally come. So the old Dart sat in the driveway for a few days as I worried how to get around without it and without any money to fix it or replace it. My roommate, who was getting annoyed about driving me to school everyday, asked me if I had ever changed the sparkplugs. I realized I hadn’t (this was ~3 years into my ownership). So I bought a set and found that 5 of those 6 sparkplugs from the old indestructible 225 slant-6 engine had gaps completely filled with carbon, which meant, improbably, that the car got over that last hill on one cylinder. Once I put in the new plugs, the engine purred like a kitten – all the power returned. The second Dart story was that the engine was running so well on the day I sold it that I could feel no vibration at all at the last stop light before I turned the car over to the new owner – I couldn’t tell if the engine was on until I pressed the accelerator.

  50. From about 1962-1988 my family only bought cars with the slant-6. When I was little I thought every car engine looked like that.

    My father had a basement and shed full of slant-6 parts. I was encouraged to do my own work, and hopped up my 1963 dodge 330 with the 4-bbl hyperpak kit. I’d pull strongly up hills and other “experts” asked me what v-8 was under the hood. They wouldn’t believe me until I opened the hood and told them to count. Those 4-bbl slant-6’s had so much torque.

    Since my dad and I, and even my mother, simply replaced everything, these cars ran until rust killed the floorboards or frame. Time to get another car for like $200 when the seat started sagging toward the ground or when you saw the road under the floor.

    Now I just heard that Fiat Chrysler has a secret project to bring the slant-6 back. I haven’t bought Mopar in many decades. But I’ll be lining up for a new one if they bring back a reasonable new version of it.

  51. Ray Martinek says:

    I use to have a 1967 D100 pickup with the 225CI. The engine and truck were both amazing. I used the truck to haul firewood from my dad’s farm to my home, about 65 miles apart. We would put about 1 1/2 ricks of wood on that truck (WAY over loaded). The engine had enough torque in 2nd gear to pull that load up a steep hill. Got 18mpg highway (empty). Very impressive truck.

  52. danie erasmus says:

    All the above, are a joke, right? Unfortunately, the italians and germans would not understand english,because they would otherwise enjoy a good joke!!!!

  53. perry hvegholm says:

    I’ve owned a few slants over the years. I bought a 68′ Dart that was a one owner car all its life. Old man that owned it had a horse track obsession. Glove box was stuffed full (literally) with parking passes from Del Mar and Hollywood Park race tracks that went back decades. The guy who hauled it out of California flipped it to me cheap, he told me it “needed a valve job pretty bad.”

    I was told it was at just over 200,000 miles. It was running on 5 cyl and had leaves, pine needles and crud caked all over the motor. I hauled it home, replaced all the rotted vacuum lines, hoses and belts. Fresh oil and filters, new plugs. It fired right up and ran as smooth as a sewing machine. Lifters clattered a little but adjusting them cleared that up.

    It was my plan to swap in a stout smallblock but it ran so well that I just cleaned it up and brought the paint back with compound and wax. I used it as a commuter and put another 100k on it. Still ran great when I sold it for 12 times what i paid for it. New owner was going to build it into an SS/AA Hemi Dart clone.

  54. perry hvegholm says:

    The Slant 6 was so overbuilt that it will take close to 20lb of turbo boost. Lots of features, forums and sites showing how folks did theirs…most of them totally on the cheap. One of the Mopar mags did a feature on a homebuilt, low buck turbo equipped Plymouth savoy thats turning consistent 12 second timeslips at the tracks. The venerable /6 earned its legendary reputation. Funny how the BMW built their own slant 6 motor.

  55. John Valandingham says:

    In 1967 my best friend’s father made us get rid of 8 junk cars in the yard..or else! , so we decided to have fun and blow the engines first. So we held the peddles down in neutral till all the engines failed… pretty darn soon, except one..yep a chrysler built slant six. We both took turns holding the peddle down till we tired, so we got a brick and let it do the work, after a while we got tired of waiting and towed the others cars away and when we got back,hours later, the damn thing was still running. We looked at each other and said “Damn, we should of kept that car!”

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