71 Exhaust System-front pipes

[Tom W.]

I am replacing the 2" exhaust on my 71 350/270 4spd.
The new system came with two extensions that are to be installed in the front pipes between the connecting flange and the Exhaust manifold/donut.

My question is: Since I have a Heat Riser Valve on the Right side, should I install both Extensions or only the one on the left side?
I assume installing both may make the right side hang a bit lower than the left.
The diagram in the AIM (UPC 8 -A2) only shows the left side details, with the extension installed, the right is shown already connected.

Thanks in advance.
Tom

[Terry M.]

Re: 71 Exhaust System-front pipes

Tom -- My 1970 has the extensions on both sides. It is the original system, however it is an LT1. I don't think that would matter since the pipes as they exit the exhaust manifold and heat riser are two-inches.

I do believe the right (passenger) side is a little lower than the left (driver) side -- but I would have to go look to confirm my memory on that point.

BTW: The doughnut is the fiber type -- FWIW.

[Joe L.]

Re: 71 Exhaust System-front pipes

I am replacing the 2" exhaust on my 71 350/270 4spd.
The new system came with two extensions that are to be installed in the front pipes between the connecting flange and the Exhaust manifold/donut.

My question is: Since I have a Heat Riser Valve on the Right side, should I install both Extensions or only the one on the left side?
I assume installing both may make the right side hang a bit lower than the left.
The diagram in the AIM (UPC 8 -A2) only shows the left side details, with the extension installed, the right is shown already connected.

Thanks in advance.
Tom

Tom-----

I assume that you're referring to the extensions that insert into the forward exhaust pipes and which "center" the "donut" packing. If so, these extensions are used on BOTH sides; it has nothing to do with the heat riser, at all. The right side forward pipe is, of course, shorter to compensate for the length of the heat riser. However, the mounting of the pipe to the manifold (left side) or heat riser (right side) is the same. The extensions have no effect, whatsoever, on the installed position of the forward exhaust pipes.

Some forward exhaust pipes are manufactured with "integral" extensions. With these, no separate extension is required or could be used.

[Tom W.]

Re: 71 Exhaust System-front pipes

Thanks Joe & Terry.

I wondered what those extensions were for- sounds like the donut would possibly move around a bit without them.
Do you recommend using Brass Nuts on the Exhaust manifold bolts?

[Terry M.]

Re: 71 Exhaust System-front pipes

If you are having the car judged the original Stover nuts are the way to go. Next best for judged cars are reproductions from any of the large suppliers -- I believe a past thread had pictures of the nuts from Paragon. They are close, and most judges haven't seen the real deal anyway.

If the car is not to be judged I would go for stainless steel -- both studs and nuts, and Joe's past comments indicate he loves stainless, but I am sure he will chime in with his own deux centavos.

[Dick W.]

Re: 71 Exhaust System-front pipes

Stainless studs and brass nuts if you do not care about a couple of judging points. With this combination you can take it apart when you want to with out worrying about frozen nuts and wringing studs

[Michael G.]

Re: 71 Exhaust System-front pipes

Dick, Is there a benefit to stainless studs and brass nuts over stainless and stainless? Mike

[Joe L.]

Re: 71 Exhaust System-front pipes

If you are having the car judged the original Stover nuts are the way to go. Next best for judged cars are reproductions from any of the large suppliers -- I believe a past thread had pictures of the nuts from Paragon. They are close, and most judges haven't seen the real deal anyway.

If the car is not to be judged I would go for stainless steel -- both studs and nuts, and Joe's past comments indicate he loves stainless, but I am sure he will chime in with his own deux centavos.

Terry-----


I love stainless for just about everything except fuel/brake lines AND exhaust stud NUTS. For the nuts, I like the LONG brass type nuts. For the studs, ABSOLUTELY, POSITIVELY stainless steel.

[Joe L.]

Re: 71 Exhaust System-front pipes

Dick, Is there a benefit to stainless studs and brass nuts over stainless and stainless? Mike

Michael-----


I think so. The stainless studs with brass nuts pretty much ensures that you'll be able to remove the nuts when you need to. Stainless nuts are OK, too, but they can still seize up on you and be difficult to remove. Usually, they'll be ok to remove but with brass the term "usually" becomes "always".

[Terry M.]

Re: 71 Exhaust System-front pipes

So your stainless steel passion has limits. I have had stainless/stainless on some of my driver cars with no issues -- and they see far more use than any of our Corvettes. That material combination survives daily use through winters here in the northern mid-west. Keeping the nuts tight is the only issue. They tend to loosen, even with lock washers.

[Harmon C.]

Re: 71 Exhaust System-front pipes

I agree that the nuts loosen over time with stainless studs and nuts either brass or SS with lock washers. The nuts from Paragon that I recived fit so tight you could not install them. I tapped them out to remove the lock part of the nut.Acutally the way most Corvettes are used today regular studs with steel nuts and washers is what I use because a little rust stops the loosening problem if you drive your car. I will never see them rust like when Corvettes were daily drivers so they will come off with no problems with heated and A/C storage like I have.