I have a '71 LS5 w/auto trans and it's about time for a new exhaust. I'm hoping to find a system that has good mandrel bends that dont reduce the 2 1/2" pipe. Anyone have any experience with Stainless Works on a 454?

 

I have not used StainlessWorks on big block, but I do have them on my small block. They are excellent in construction and welding, but as you know they are expensive. The fit has been a problem on every exhaust I have tried, including StainlessWorks.

 

Don't get too hung up on mandrel bends if the car is making around stock power.......you are probably going to run the manifolds right? If so.....mandrel becomes kind of a moot point.....flow is not optimized right out of the cylinder head anyway.
The stock system on these cars was a pathetic 2" system after 68........you can bolt a factory 68 system (2.5") on with N-11 mufflers and pick up a ton.....or you can do what I did on my 69' 427/400 and install the Willcox 2.5" chambered system which made that car breathe a LOT better......(bone stock except .060 bore and 268H Comp cam)......I bolted the system on in 2 hours and that included cutting the old system off. Fit perfect. Aluminized pipe looks good for a long time......I would not waste money on Stainless.
Pypes makes a 2.5" mandrel system if you have to have it......but I think those guys are ******** and would not recommend their product over that reason alone. I have their X-Pipe and a pair of mufflers I bought from Forum members and they are super high quality......although I have heard from more than one person that the whole system does not fit well......X-pipes do sound a lot better IMHO.....
Can you believe that GM built L-88 Vette's with a 2" exhaust system? A lot of the drivability issues of these cars AND the L-71 were this exhaust system and the timing spec alone......they really had their head in their *** back then......

Jebby

 

I have them on mine also. They were very easy to install and the car runs great with
them. Ncrs does NOT like them though it’s worth it.

 

Jebby, the engine does have some mods. Ported heads with big valves, ported intake and exhaust manifolds, LS6 pistons at 9.5:1, Magnum 270 cam, LS7 crank.

I noticed that Jegs has an Aluminized version of Stainless Works exhaust system for $380 shipped. Seems like a pretty good deal if it fits correctly.

 

Get an Allen’s chambered system the car will breath like never before!

 

Run some headers and let that baby talk to you

Jebby

 

I gave that some thought, but I decided to maintain a stock appearing sleeper.

I ported the AIR bosses out of the stock manifolds which works well. When the engine was stock it ran 8.2 at 79mph in the 1/8th. After my engine work the et dropped to 7.7 at 84mph, which should put it around 12 flat in the 1/4. Not bad for what appears to be a bone stock LS5.

 

Sounds like sneaky fun

Jebby

 

Are you sure about this? Even in '72, all LT-1s and LS-5s had 2.5" pipes.

 

Yes....69’ only.....all Vette’s had 2” exhaust front to rear....in 70-72 they reverted back to 2.5” in hi-po applications....but ALL have a 2” outlet at the muffler.

Jebby