Question About the 502 Retro-Kit Truck GM Performance Parts Crate Engine

[1-ton]

[ QUOTE ]
This new emission-legal 502 cubic-inch (50 state) Retro-Kit engine conversion kit from GM Performance Parts is designed for 1991-93 Chevrolet and GMC 10, 20 and 30-series trucks with 2-wheel drive, originally equipped with a 454 TBI engine and 4L80E automatic overdrive transmission. (Will not work on 4 wheel drive because of exhaust interference)

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My question is about the last part "Will not work with 4-wheel drive because of exhaust interference".

does this remain true with aftermarket shorty headers?

 

[4X4HIGH]

If you already have a BBC in your truck and just want the bigger cubes it will fit. If the engine comes with manifolds already installed then maybe they won't fit a 4WD chassis but then you just use your existing manifolds or headers.

 

[1-ton]

Actually my truck came with a 350, but a 454 was an option for it. If I where to put this 502 into it, I was going buy aftermarket headers for it and a whole new exhaust system for it anyway; along with many other changes. The exhaust system for a 502 has to workout some way on a 4-wheel drive or else it would kill 80% of the market out there that would purchase the Big Block 502.

I wonder if they mean the IFS 4-wheel drive trucks, and not straight-axle trucks like mine?

 

[84gmcjimmy]

Maybe it means you need to snip your frame a bit so the headers/exhuast will fit? /forums/images/graemlins/dunno.gif

 

[jwduke]

Re: Question About the 502 Retro-Kit Truck GM Performance Parts Crate Engin

Isn't a R20 & R30 2 different vehicles (frames) completely the R20 being IFS, and the R30 being Solid axle? I can see having clearance problems with a R20, because of IFS.

 

[1-ton]

Re: Question About the 502 Retro-Kit Truck GM Performance Parts Crate Engin

[ QUOTE ]
Isn't a R20 & R30 2 different vehicles (frames) completely the R20 being IFS, and the R30 being Solid axle? I can see having clearance problems with a R20, because of IFS.

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I think it something goes like this, but not positive.

C 15, 25, 35 are two-wheel drive Generation 3 body style

K 15, 25, 35 are an IFS four-wheel drive Generation 3 body style

V 25, 35 is a straight axle four-wheel drive with the old generation 2 body style (no V15 exists I think, but not positive)

R 25, 35 is two-wheel drive with the old generation 2 body style (no R 15 exists I think, but not positive)


The 502 replacement engine is for the generation 3 body style two-wheel drive C 20, 30 GM trucks. They say it will not fit the four wheel-drives because of exhaust clearance issues, but I wonder if that is with the IFS four-wheel suspension; and not the solid axle because the IFS trucks have a huge cross member, which could cause interference that the solid axle does not have. I would think that if a truck can clear a 454 exhaust system, then it should be able to clear a 502. I think the 502 is the same block and heads as a 454, but just stroked like a 350 is to a 383.

 

[afroman006]

Re: Question About the 502 Retro-Kit Truck GM Performance Parts Crate Engin

Tecnically, the 502 is to BBC's as the 400 is to SBC's. Same size block with siamesed cylinders, bigger bores, and longer strokes.

 

[jwduke]

Re: Question About the 502 Retro-Kit Truck GM Performance Parts Crate Engin

[ QUOTE ]
[ QUOTE ]
Isn't a R20 & R30 2 different vehicles (frames) completely the R20 being IFS, and the R30 being Solid axle? I can see having clearance problems with a R20, because of IFS.

[/ QUOTE ]

I think it something goes like this, but not positive.

C 15, 25, 35 are two-wheel drive Generation 3 body style

K 15, 25, 35 are an IFS four-wheel drive Generation 3 body style

V 25, 35 is a straight axle four-wheel drive with the old generation 2 body style (no V15 exists I think, but not positive)

R 25, 35 is two-wheel drive with the old generation 2 body style (no R 15 exists I think, but not positive)


The 502 replacement engine is for the generation 3 body style two-wheel drive C 20, 30 GM trucks. They say it will not fit the four wheel-drives because of exhaust clearance issues, but I wonder if that is with the IFS four-wheel suspension; and not the solid axle because the IFS trucks have a huge cross member, which could cause interference that the solid axle does not have. I would think that if a truck can clear a 454 exhaust system, then it should be able to clear a 502. I think the 502 is the same block and heads as a 454, but just stroked like a 350 is to a 383.

[/ QUOTE ]

Yeah, thats what I was trying to say, thanks!!! I agree with you 100%.

 

[1-ton]

Re: Question About the 502 Retro-Kit Truck GM Performance Parts Crate Engin

[ QUOTE ]
Tecnically, the 502 is to BBC's as the 400 is to SBC's. Same size block with siamesed cylinders, bigger bores, and longer strokes.

[/ QUOTE ]

I was not sure exactly how they got the 502 cubic inches, but I thought I remembered back when the 502 first came out an article said it was based on the "Mark IV" Big Block casting.