I am new to the Corvette hobby, I recently purchased a 1972 corvette that I have nicknamed "The Hack" It was originally a base 350 4 speed car. However, it now has a late model (87-88) 305, headers, TH350 auto, and mallory unilite electronic distributer w/ tach drive. Since the drivetrain is nowhere near original I would like to install a mildly built (about 370 HP at flywheel) 454. What would installing a 454 in a vette entail. Will the TH350 and IRS live behind a healthy big block and will the small block brackets (A/C, alt, power steering, etc) adapt to the 454 or do I need all new brackets. Any input will be greatly appreciated. My goal is to retain the stock looks but have a little something extra under the hood. I have had a number of small block pony cars (Chevy and Ford) but I want to experience the torque of a 454 in something lighter than a pickup :D

 

This question is asked every few weeks on this forum. My response is the always the same " The same question was asked in one of the vette mags and the answer from the tech. guy in the mag was (forget it It) It will be to costly to do properly. Cheaper to buy a BB vette.

 

73-454:
I totally disagree. It cost me $4500 to completely build my 454...it could have been done a lot cheaper but I went into the rebuild with a hi-performance approach. A 454 with a decent set of heads and a healthy cam can easily put out 400HP. Getting 1HP per cubic inch is not that hard either. I say if he likes his 'Vette don't sell it to simply get a big block 'Vette...build a big block and drop in it (it's not that hard, nor is it as expensive as some make it out to be).

srmcclean:
A 454 will bolt right into your '72. You will need big block pulleys, big block alternator/AC/power steering brackets. If you decide to run exhaust manifolds instead of headers you will need Corvette specific exhaust manifolds....regular ones will not work. Your TH350 transmission and drive train should hold up just fine with your target engine power. Your drivetrain parts will actually last longer (all things being equal) than if you had a standard transmission.

Please note that 454s are externally balanced so you will need a 454 flexplate should you decide to go with an automatic. You will also need a big block short style water pump. Most likely the water pump on the 454 that you have is a long style, a Corvette uses the short style do to the position of the radiator. It's not that hard to do, in fact I just finished dropping a 454 into my '76. Good luck and if you have any questions feel free to ask.


[Modified by bence13_33, 1:36 PM 5/19/2002]

 

I'll let others that have gone with the swap get into the details such as Bence who just got done with his. As far as the drivetrain and suspension the big blocks did have a few small differences, the biggest one I can think of is the rear u-joints, BB cars came with capped U joints on the rear axles while the small blocks came the normal band style, depending on how hard your going to be on the car and how well it hooks you may be fine with the regular band style on the u-joints if you don't plan on drag racing with slicks or very large meats. Remember horsepower doesn't brake parts, torque does, so a 370 hp 454 depending on how it was built still may make well over 500ft/lbs of torque so keep this in mind. The th-350, may be fine if it's in good shape and depending on how much torque your planning out of that BB, chances are it will be fine in a semi light car like a vette but upgrading it to a higher torque rating wouldn't be a bad idea to be on the safe side while you have the engine out anyway. Everything realy depends on what you want the car to do, I personally find BB's with 4spds to be great fun myself. Once you've gone rat you won't look back :D

:cheers:
Pat Kunz

 

Thanks for the input guys, I am still agonizing over the small block vs big block question as I now have acess to a good running 350 for cheap! but the 454 keeps calling me :)

 

Mine was a small block and is now a BB but I didn't do the change. It does fit and doesn't look too difficult (easy for me to say since I didn't do it)

 

I vote for the small block. I'm having a blast trying to get my "little" 350 to run in the low 12s. I'm in the upper 12s now. I could easily do it with a big block but have to much into the 350 now. I like a challenge :yesnod:

 

73's and up are easier because the stock hood works... 68-72 will need at least a BB hood. Even with that you are limited to the stock Corvette intake and carb set-up... An L-88 hood gives more options.

 

I cast my vote for the BB conversion. I'm working on a 454 swap right now and will have a similar setup as Bence. The torque curve on the BB is flatter and properly configured should not drop below 450ftlb above 2000rpm(hopefully more). Building a nice SB will get you to a peak of 450(maybe).

 

I am leaning toward the big block, My car already has a 73 and later hood in fact it seems to be raised slightly higher in the center than a stock 73 hood. I have seen many "built" small blocks that run in the 15's (usually in older camaros)However, almost all the big blocks I have seen in cars with similar weight to our Corvettes usually run at least in the 13's. I am looking at getting a running 454 "freshen" it install new cam, lifters, valve springs, intake, headers. and good old quadrajet. Hopefully it will run at least 13.50's while retaining all power accessories and A/C (I live in hot orlando). :D

 

Drop in the big block. My only suggestion would be to go with a TH 400. You should also install the heavier rate transverse leaf spring in the rear. It will be a project, but you won't be sorry you did it. You could build a small block that would gve you just as much of a thrill to drive, but it just looks good to see the RAT under the hood. I drove a '72 454 automatic for twenty nine years and enjoyed every minute of it. Good luck.

 

Just ask Monty to see what he thinks about small blocks potential :lol: !

 

Those SB need real builders. That is stock perf.! Your 370 hp is no problem for a sb, a bb will do that through stock manifolds & restrictive sidepipes. Installing a BB is no big deal.

:cool: