71 LS5 Engine Pipes

[Kenneth T.]

Some pics of my engine pipes from my 71. I was curious there is a part # on the left pipe but none on the pass side? As you can see they are the double wall with all the crimps. Anyone know why only one pipe is numbered?



Ken

[Terry M.]

Re: 71 LS5 Engine Pipes

1) the number is sumplace you haven't seen yet.
2) Somebody Fed up.

[Joe L.]

Re: 71 LS5 Engine Pipes

Some pics of my engine pipes from my 71. I was curious there is a part # on the left pipe but none on the pass side? As you can see they are the double wall with all the crimps. Anyone know why only one pipe is numbered?



Ken

Ken------


I don't think the left side forward pipe is original to the car. Your car should have used left side forward pipe GM #3973875. This pipe was used for 1970-72 Corvettes with big block.

The GM #334929 was used in PRODUCTION for 73-74 LS-4. It became the SERVICE piece for 1970-72 when the GM #3973875 was discontinued in December, 1972. I would not rule out the possibility of the 334929 being used for late 1972 Corvettes with LS-5, but I really doubt it would have been used as early as 1971.

I don't think that the predecessor 3973875 had a part number on it, but it's possible it did.

Your right side pipe should be a GM #3869584. This piece dates back to the 1965 model year and was used through 1972. It did not have a part number stamped on it. Your right side pipe could also be its replacement, the 1973 model year released GM #334932. This piece sometimes does and sometimes does not have a part number stamped on it. It replaced the 3869584 for SERVICE in March, 1973.

So, why would someone have replaced at least the left side forward pipe, a part which rarely needs to be replaced? That we could only speculate on. However, it MIGHT be a very subtle indication of some nefarious goings-on.

[Kenneth T.]

Re: 71 LS5 Engine Pipes

Ken------


I don't think the left side forward pipe is original to the car. Your car should have used left side forward pipe GM #3973875. This pipe was used for 1970-72 Corvettes with big block.

The GM #334929 was used in PRODUCTION for 73-74 LS-4. It became the SERVICE piece for 1970-72 when the GM #3973875 was discontinued in December, 1972. I would not rule out the possibility of the 334929 being used for late 1972 Corvettes with LS-5, but I really doubt it would have been used as early as 1971.

I don't think that the predecessor 3973875 had a part number on it, but it's possible it did.

Your right side pipe should be a GM #3869584. This piece dates back to the 1965 model year and was used through 1972. It did not have a part number stamped on it. Your right side pipe could also be its replacement, the 1973 model year released GM #334932. This piece sometimes does and sometimes does not have a part number stamped on it. It replaced the 3869584 for SERVICE in March, 1973.

So, why would someone have replaced at least the left side forward pipe, a part which rarely needs to be replaced? That we could only speculate on. However, it MIGHT be a very subtle indication of some nefarious goings-on.

Joe,

Thanks I always value your input. Here comes the BUT. I am the original owner of this money pit and while I have changed the mufflers and intermediate pipes, the engine pipes have held up really well and were never changed that I remember. They are still very heavy with no rust.

As you know, when I changed the rear section of the exhaust the sound was different, tinny and not the resonance of the original.

I sometimes have to correct my memory because I did not care or think about some of the changes I made back then way before I had ever heard of the NCRS. So, my point is trying to share, what I believe is some original pipes with some very interesting crimps and depressions from tooling.

My car is a late build, last day of production. If they are not real, I have the hottest MAZDA on the block

Ken

[Bill C.]

Re: 71 LS5 Engine Pipes

Ken,

You can still find the NOS mid pipes as well as the 385/386 mufflers.

I spent 3 years hunting down all the NOS pipes and mufflers (with "W").

You are 1000% correct about the sound - the NOS stuff will get you the "growl" back. I sat my car next to a 71 BB with a Corvette Central welded system - night and day difference.

I can give you a number for a guy in S. Cal. who has three big-ass warehouses full of NOS stuff, and I know he has the pipes and mufflers.

Let me know....

[Joe L.]

Re: 71 LS5 Engine Pipes

Joe,

Thanks I always value your input. Here comes the BUT. I am the original owner of this money pit and while I have changed the mufflers and intermediate pipes, the engine pipes have held up really well and were never changed that I remember. They are still very heavy with no rust.

As you know, when I changed the rear section of the exhaust the sound was different, tinny and not the resonance of the original.

I sometimes have to correct my memory because I did not care or think about some of the changes I made back then way before I had ever heard of the NCRS. So, my point is trying to share, what I believe is some original pipes with some very interesting crimps and depressions from tooling.

My car is a late build, last day of production. If they are not real, I have the hottest MAZDA on the block

Ken

Ken-------


It absolutely amazes me that a GM #334929 would have been used for a 1971, even a last-day-of-production 1971.

As far as the "crimps" in the pipes go, both the 66-69 pieces and the 70-74 pieces had those. Those were common to all GM PRODUCTION and SERVICE pieces.

As far as the left side GM #3973875 (70-72) and the 334929 (73-74) as well as the right side GM #3869584 (65-72) and 334932 (73-74), I've never been able to discern any difference between the earlier and later pieces. I don't know why the part number changed. However, I know there had to be a difference somewhere; I just haven't figured it out.

[Edward C.]

Re: 71 LS5 Engine Pipes

Bill if possible I would like to have the number of the guy in So. Cal. who has NOS stuff. Thanks. Ed.