The Stovebolt Site Forums The Shop Area The HiPo Shop '71 C20 454 fitment?

I own a '71 C20, 350 eng, TH350, long bed, coil rear springs, 4:10 posi rear. I would like to install a 454 BB, and I'm concerned with clearance for headers. This engine is currently installed in my '86 K1500. *Also, I know I've got size issues with an aftermarket "Be Cool" aluminum radiator. Do you'all know of anyone installing a 454 in a stock C20? I believe it should bolt right up to the TH350. Thanks in-advance for your comments & info.

The 454 will bolt right in, just need the correct motor mounts. The 396/402 was a factory option on thes trucks, so it won't be an issue. I would suggest going to a TH400 behind that big block, though. That's what the original BB trucks ran.

Or go with a 4L80E and trans controller to get overdrive.

I have a 700R4, but it's for a 4WD truck. Thanks for the replies. I'm mostly worried about clearance for the headers, and that $600.00 aluminum radiator. I was going to put this '71 cab & front clip on a built '86 GMC 4x4 frame. I've decided to keep the '71 stock except the engine. I love my 454, and I know it will breath new life in my C20.

The 454 will bolt in on 350 mounts, they are in the same location. A decent set of headers should clear all your accessories. If your current radiator is keeping the 350 cool, it should do OK in all but extreme conditions with a 454. Same with your TH350.

Devin

I agree the 454 will bolt in, but my experience with big blocks is they make lots of heat. I'd look for a bigger radiator like they used in big block trucks.

And if you stay the the TH 350 either drive real nice or carry a spare.

I'll take it easy on the TH350, but I've been told that tranny can be beefed-up to handle 500 HP. Don't know if that's true. My 454 only puts out 365-375 HP, I think I'll be okay. My aluminum "Be Cool" radiator is currently installed in my '86 GMC, I'll have to fabricate brackets to implement its installation in the '71's radiator core support bracket. Inner fender wells might be a problem touching my headers. So, I might just use stock exhaust manifolds, if I can locate some. Otherwise, I'll trim/beat a little metal out of the way. Thanks again for the responses.

Jeff, Jegs have a alum. radiator that you can pick the size. I bought a double core for less than 250 and it is great.

Thanks for the Jegs info. I have 2 electric fans located on the back side of the radiator, and a third one in front, for pushing air (for emergencies only). I think it would save a lot of money if I could retro-fit/shoe-horn this radiator onto the '71's core support bracket.

I still say, go with a 4L80e and controller. The 4L80E is the transmission that GM put behind the 454's and 496's. Its an electronic overdrive version of the old TH400

http://www.tciauto.com/Products/Electronics/default.asp