Good afternoon!

Im soon to buy a nice 75 Vette stingray with the L82 motor.
Its mostly stock, but seems like one of the best performance upgrades I can do is replace the exhaust with a 4inch exhaust system, but Im looking for the best muffler to go with it, or better yet, an exhaust/muffler combo to order for my local shop to install.

Im not scared of buying primo stuff, if its worth it and not diminishing returns (aka worth it lol).

Please help a newbie out!

I had a c7 14 model but sold it due to covid, now I want a classic that wont depreciate AND get into the classic collecting of cars!

 

A good true duels exhaust system is well worth the effort.
You may wish to rethink the size however. I'm thinking 2 1/2 inch would be a much better choice.

 

How would you ever route a 4" system under a Corvette?

 

Hooker-style sidepipes dump into 4" tubes. I don't think you can fit them under the car, though.

Please post some photos! You can get a lot from exhaust and a tune.

 

Long tube ceramic coated headers and a nice 2.5" dual exhaust is one of the best mods you can do to your Vette.......especially the L-82.....when you do the exhaust and put a proper curve and timing specs for the distributor....the L-82 runs very well.....high 14 second potential....

Jebby

 

There's no way a 4" pipe would fit through the crossmember...

Corvette Central sells both a header or stock manifold complete 2 1/2" dual system with Magnaflows that's high quality.
Unplugging the exhaust would be my first move...

 

For mufflers, just get a good-flowing mufflers that sounds good to you. (You need to listen to online audio clips of the muffler.)

Basic rules: Baffled mufflers are "noise makers" that will break internally and will restrict power if you have a decent performing engine. (Might not matter on a stock L82, though.) Personally, run away from Flow Killers...

Straight-through mufflers that you can see through are the safe bet for performance and in general the longer the case, the more they reduce the noise levels.
You want 2.2 CFM / HP to not create a restriction. If you managed 300 crank hp out of a slightly modified L82, you'd need about 660 CFM muffler air flow or 330 CFM each. (Muffler CFM ratings can be hard to find from most companies, though.)

Hooker Aerochambers sound great, are 324 CFM each for the 2.5" and $95 each when I last checked 2 years ago... (They're not tiny, though.)
The BlackWidow Venom 250s are $129 and I think sound great, too.

Engine Masters did a muffler dyno a couple of years ago and found that most performance, straight-through mufflers of the same diameter made the same peak power, but the Black Widow Venom and Borla mufflers made more low end torque. I saw a Mustang muffler dyno test that ALSO showed Borla mufflers making more low-end torque than a bunch of others. I'm not sure if they just manage the velocity through the muffler better some how, but that's the 3rd time I'd seen dyno comparisons where Borla had a slight edge on low torque. (They should have some kind of edge giving the price of some of their mufflers...)


Adam