Chevelle big block exhaust manifolds on 71 MC

[silver71mc]

Getting ready to replace exhaust manifolds on 71 MC with 402. Looking at a pair Ground Up parts has for big block 67-72 Chevelle, will they fit 71 MC with 402?

 

Thanks, Paul

[cny first gen 71]

I dont belive so 71 and 72 are the same 70 and older used a heat riser on drivers side.

[70 Iron]

Hi Paul,

I have bought 2 sets of these Fac cast Manifolds from Groundup .

One set is on my 70 454 ,I also used the factory down pipes,

The second is on the 427 that I have to go in my other 70 Monte and also using the factory down pipes. I don't use the heat riser but Groundup has a spacer that takes place of them.

I've had no issues with the 1st and expect none with the one I'm doing now.I only had to grind the bottom for the GM crate enging because of the tall head bolts. If you are using the 402 this would'nt be a problem.

They also have the ones for the smog air tubes.

Any more info you need let me know.

 

Terry

[silver71mc]

Hey guys thanks for the reply. When I remove the motor, I'm going to eliminate the entire exhaust system. After the motor is reinstalled I thought I would take the car to a muffler shop and have a custom system installed. Shouldn't need the heat riser, right? I most likely will not be driving the car in really cold weather.

Thanks, Paul

[cny first gen 71]

No you dont need heat riser but make sure the manafold has the rescess for the gasket and try to find a steel gasket if you can they are much better than the fiber ones.

[silver71mc]

Checked manifolds, they are recessed for the donut gasket. Will use the steel ones. Just wondering, how much modifying has to be done to run shorty headers? It's a big block with a/c and power steering.

Thanks, Paul

[monte70car]

You will probably need to change out the down pipes to make the shorty work. If you did the full length header the lead pipe will need to be changed. Both the a/c and power steering will work with either header.

[70 Iron]

Paul, The manifolds that I bought from Groundup and Ausley's had a flat surface on the right bank for a

"Flat Gasket"and for one side of the riser and a recessed area on the bottom for the donut.The riser spacer which I bought had the flat end to fit the top and a recessed area for the donut on the other end.

I think that you'll need either the heat riser or the spacer to use the factory down pipes.The riser spacer has the same thickness as the funcional riser but has no insides.Groundup sells them too.

I ordered my down pipes from Classic Exhaust,they are made to factory specs and for the riser or spacer,he even flatten them for me where the cross member goes just like the original ones were. $160.00 shipped.

www.Classicexhaustinc.com

Ph# 440 466-5460

 

 

Terry

[silver71mc]

Guys thanks again for the help and info. Pics on Ground Up site show beveled edge on both manifolds, also shows longer studs for one side of the manifolds. Should order spacer, gasket and studs. Think I will call Classic Exhaust to see what it cost for manifold to muffler, and muffler to tips pipes. When we start working on the car I'll try to send some pics.

Thanks, Paul