Mailbag: Rejuvenating an Old 454 Big Block Chevy

[Image/Michael Barera, Creative Commons Attribution-Share Alike 4.0 International]

Q: I have a 1973 454 big block Chevy. It has a 8.5:1 compression, stock oval port cylinder heads, a Crane PowerMax camshaft, and Edelbrock Performer intake, and a Holley 750 cfm carburetor.

The engine needs an overhaul but I would like to retain the stock cylinder heads and intake. What would I need to increase the compression ratio?

Also, I enjoy the sound of an aggressive cam—what do you recommend? I want it to be a stout street engine, and still have some fun on the track!

A: Thanks for writing! After poking around a little, we think we’ve found a great combination to transform your engine into a street-and-strip powerhouse.

For starters, you can rejuvenate your engine with a Sealed Power premium engine rebuild kit.

It includes everything you need for an extensive overhaul without breaking your budget, plus you can retain your stock cylinder heads and intake. Once you’ve installed the kit, your compression should increase to around 9.8:1.

Keep in mind that these kits are custom ordered according to your bore diameter and bearing sizes. You can talk to our tech-expert friends at Summit Racing to make sure you’re getting the proper kit for your specific application. (You can reach them by phone at 800-230-3030.)

As for your camshaft, we recommend a COMP Cams Xtreme Energy cam and lifter kit. It includes a hydraulic flat tappet cam that builds big power from 2,300-6,500 rpm and has 240° int./246° exh. duration @ .050”.

Also included is a set of lifters, a timing chain and gears, valve springs, seals, and locks, retainers, and assembly lube.

The aggressive lope of the Xtreme Energy cam will be music to your ears. Best of luck building your powerplant!

This is another in a series of weekly Q&A Mailbag sessions with Summit Racing‘s tech department, in which there are hundreds more. Click here to see them all.

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  1. Morrece M King says:

    I just rebuilt a big block about 8 months ago.I don’t know did my mechanic built right I woke up one morning and didn’t want to start got another mechanic he told me it’s was lock up I pour alot of money in that motor so if you do it do it right.

  2. John Klein says:

    Alot of people never think of an old trick my daddy taught me, have your heads shaved and that will up your compression also.

  3. Adrion Hale says:

    Cam not good for the street and there are many more factors to consider than provided in your question such as, vehicle weight, gear ratio, transmision stall ect. You want more low end torque. Torque wins races. Most importantly is where you want to build the torque curve. 2,500-3000 rpm is hwy speed. You won’t need a cam that delivers up to 6,000 rpm. Get a cam that kicks in at 1000-1500 rpm and run a closed chamber intake with that holley and you’ll pull tree stumps. Contact lunati cams and tell them what you have. They are very helpful.

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