70 LT-1 exhaust question

[Kim B.]

I am restoring a 1970 LT-1 with original secondary exhaust pipes (under trans to muffler) and mufflers. My question is should I keep these on the car and paint them or replace all of it. They are in good shape, they just look a little rough. I have never had a car judged and trying to get this one ready for the Texas regionals. Any help would be appreciated!!

[Terry M.]

Re: 70 LT-1 exhaust question

The only paint on C3 mufflers was a black-out operation on the mufflers. This is described in words in the TIM&JG and there are some pictures in earlier threads.

[Jim T.]

Re: 70 LT-1 exhaust question

Kim I can't recommend what you do. If your pipes are the true originals and if they are constructed like the originals on my 68 327/350 your exhaust pipes will have double layered steel. I do not believe you will be able find new exhaust pipes made like the originals.

[Kim B.]

Re: 70 LT-1 exhaust question

The pipes are double layered but not shinny and new. I painted the mufflers with high heat aluminum and left the pipes alone. I get the feeling from you that no paint on old pipes and mufflers would be better than painting them. What would you do? Thanks!

[William C.]

Re: 70 LT-1 exhaust question

If you have genuine originals I'd clean them up as best I could without getting too aggressive and put them on the car. A small condition hit for real parts is generally better the all the issues with reproductions with regard to shape and configuration of the bend areas.

[Joe L.]

Re: 70 LT-1 exhaust question

I am restoring a 1970 LT-1 with original secondary exhaust pipes (under trans to muffler) and mufflers. My question is should I keep these on the car and paint them or replace all of it. They are in good shape, they just look a little rough. I have never had a car judged and trying to get this one ready for the Texas regionals. Any help would be appreciated!!

Kim-----


Are you saying that you have original pipes AND MUFFLERS? If so, I find it absolutely amazing that the mufflers, ESPECIALLY the right side muffler, have lasted this long.

[Kim B.]

Re: 70 LT-1 exhaust question

Joe, I was surprised too, but these seem to be the originals. Pipes are very heavy, crushed to an oval shape at the differential, and mufflers have the "W" on them. The pipe and muffler is all one piece too. I don't know how good the mufflers are because I have not run the engine through them as yet. I also looked at the other threads and guess I better shoot a little black on them. Thanks

[Terry M.]

Re: 70 LT-1 exhaust question

I am restoring a 1970 LT-1 with original secondary exhaust pipes (under trans to muffler) and mufflers. My question is should I keep these on the car and paint them or replace all of it. They are in good shape, they just look a little rough. I have never had a car judged and trying to get this one ready for the Texas regionals. Any help would be appreciated!!

Kim -- I would leave the pipes alone. There is nothing you can do to them that will improve the finish, and a lot you can do that will make it worse.

There have been several C3 muffler blackout threads in the past. I don't have many pictures of that now, but I will in a month or two. I think some others have posted them though.

Most of the guys just use BBQ black on the mufflers -- it is a fair facsimile, but not quite like the real deal -- but then I don't think anyone has come up with what it was they coated them with originally.

[Dave S.]

Re: 70 LT-1 exhaust question

I am restoring a 1970 LT-1 with original secondary exhaust pipes (under trans to muffler) and mufflers. My question is should I keep these on the car and paint them or replace all of it. They are in good shape, they just look a little rough. I have never had a car judged and trying to get this one ready for the Texas regionals. Any help would be appreciated!!

Kim,
As a fellow LT-1 owner I will tell you that having an original exhaust system is an exterme rarity. I highly recommend you use it and if not preserve/save it for future use. The center/rear pipes and mufflers are the same as big block cars but the header pipes are unique to an LT-1 car as the pipe goes from 2 inches at the manifold to 2 1/2 inches immediately after the manifold. Original pipes will not have a weld present to accomplish this. The center/rear pipes will have the "wrinkle" bends where the changes in direction take place. No clamp will exist just ahead of the muffler. The header pipes will not have the wrinkles but will have the unique change in diameter mentioned above.
With the original system you will get all the originality points and will lose a few condition points. No aftermarket system will do much better than that and most will do worse.
I agree with Terry in that you should just leave it alone as far as the rust is concerned.

[Terry M.]

Re: 70 LT-1 exhaust question

Kim,
No aftermarket system will do much better than that and most will do worse.

Dave -- I'm not so sure that the new Gardner system will not do as well, and maybe better -- at least until they also rust. I have not yet had a chance to see that system on an LT1, but it looked pretty good on a BB.

[Dave S.]

Re: 70 LT-1 exhaust question

Dave -- I'm not so sure that the new Gardner system will not do as well, and maybe better -- at least until they also rust. I have not yet had a chance to see that system on an LT1, but it looked pretty good on a BB.

Terry,
You may be right about that but some originality will be lost due to lack of the "W" on the mufflers. I haven't seen the Gardner LT-1 header pipes so I can't comment there. The other difference in the Gardner system is that it is Aluminized. No carbon steel so I'm told.

[Terry M.]

Re: 70 LT-1 exhaust question

Dave, You are right on both counts -- although the BB system I saw had an owner-inspired W on the mufflers. It was necessary for the owner to add the blackout to the mufflers. I think this owner did some changes to the supplied clamps also.

[Mike E.]

Re: 70 LT-1 exhaust question

My 71 LT-1 with 30k miles has original exhaust all the way to the tips. It was taken off very early in the car's life and replaced with headers and side pipes. It's back on the car, and fits unbelieavably well. It's been used at an NCRS national on the rack for the judging school as an example of what the original exhaust looks like.

[Kim B.]

Re: 70 LT-1 exhaust question

Mike, tell me what your exhaust look like. Do they have blackout on them? Any other characteristics? Thanks

[Joe L.]

Re: 70 LT-1 exhaust question

Joe, I was surprised too, but these seem to be the originals. Pipes are very heavy, crushed to an oval shape at the differential, and mufflers have the "W" on them. The pipe and muffler is all one piece too. I don't know how good the mufflers are because I have not run the engine through them as yet. I also looked at the other threads and guess I better shoot a little black on them. Thanks

Kim-----


I would check the right side muffler in the area below and adjacent to where the exhaust pipe attaches to it. This is usually the area that goes first. It rusts from the INSIDE out and does not start "peeking through" until it's pretty well gone. Once the internal rusting begins, it proceeds inexorably.