383 vs 454 for Pro-Touring/Auto-X

[ccoyle3]

My son and I are building up a 77 Z28 as a pro-touring car for street fun and to run in local autocross events. The car has a mild 350 in it which seems a bit tired, but will work for the mean time.

We want to start building a replacement motor. I think a 383 would be ideal from a power/weight standpoint. However, we have a complete 454 motor that was removed from an older pickup. I am wondering if it doesn't make more sense to rebuild the 454 and swap it in. I'm thinking that with some head work, cam, headers and carb, the big block would produce ample power and torque for our application and would cost less than builing a 383 from the start.

On the other hand, I am concerned about the extra weight and its effect on handling. Want the car to be fun to drive and not handle like a complete dog. Also how difficult/expensive would the big block swap be.

Any thoughts or suggestions along these lines would be greatly appreciated.

[formula]

sounds like you've already got your head pretty much in the right place, man. You can make a big block car handle pretty well, but every bit of weight you save is that much less spring, shock, tire, etc you have to run to get equivalent handling characteristics AND how much hp you'll need to go as fast. you'll have to decide, in the end, if cost or performance is your highest priority. I can tell you that moving from an iron block, iron head 350 to an all-aluminum 366 made a HUGE difference in the overall behavior of my car, allowing me to back my shocks way down and improve ride quality a lot without sacrificing handling.

Why not just build the 350?

[Rod]

I'm going to vote for a good 350 with aluminum heads, or the 383 you were thinking about, the handling characteristics will be better with the small block the car will be more agile, thats even why nascars are 358ci, indy cars are 3.0 liters(small block V8) at least Chevy is Ferrari is a 3.0 liter V10(still small), even Circle Track cars use a small block,
Now there's nothing wrong with a Big Block racer, but after many years all the big race organizations have all come to realize that a more agile car is safer, and enforce the small engine size

[6'9"Witha69]

I say SBC.

[Vegas69]

Big block low end torque is nice for autocross. I've outrun Nissan GTR's, Vipers, C6's, local ASP club champ with my aluminum headed big block. It's really a trade off of a little better handling vs. more acceleration out of slow corners in my eyes. I do have r888's on the car and a DSE sub. The ASP champ does run A6's with 315mm on all four corners. I'd go with what you prefer off the race track as well. Big block cars tend to have more value than small block cars. I may be a little biased, I'm building a ZL-1 big block that will weigh only 500lbs right now. Big blocks aren't cheap to build. That engine could very well be a can of worms. You may want to tear both engines down and assess your situation.
http://www.youtube.com/watch?v=Wkas7OaFACc

[Lowend]

Winning auto-x cars are light; not powerful.
Power only moves you in a straight line. Low mass lets you do everything easer.

In other words, build a smallblock.

[TnBlkC230WZ]

A well built small block with have all the torque out of the slow corners that you tires can put to the ground. The difference is with a BBC, you'll put it in second gear and mash the gas. With an SBC, you'll be working first and second.

[406 Q-ship]

Go for the balance and use a SBC, BBC will push to much weight over the front tires.

[Vegas69]

You guys have to check out the Speedtech Camaro in Super Chevy. ALL IRON big block outgunned most of the competitors...

[66chad]

I noticed in your post u said also for street fun. 454 with aluminum heads you couldn't wipe the smile off you and your sons face.

[tonykim]

I'd say do the 383. Should be able to get reliable 500 hp and 500 ft. lb of torque at 9.5:1 and on pump gas.

Check out this link at AFR's website for 480-500 hp 383 combos that make 450 ft-lb at only 2500 rpm. That should be a lot of fun.

http://www.airflowresearch.com/chevy_dyno.php

[sovain]

i vote small block with twin turbos!

[1969CamaroRS]

I noticed in your post u said also for street fun. 454 with aluminum heads you couldn't wipe the smile off you and your sons face.

Exactly, for street fun = low end torque; and BBC is the king of torque.

[mroth]

I got the most bang for the buck by getting a stroker kit for a 454 making it a 496. I am running 10.4 -1 compression with iron heads and should produce just under 650hp and still running with super unleaded gasoline. I got it all built for under $4,000 with quality parts. I am going with the same setup in my 67 Camaro now. I thought a supercharger would have been nice but I couldn't fit it under the hood. The same horsepower would have been a couple thousand more to build.