Top Flight L-82 exhaust question

[Michael C.]

I own a '77 L-82/M-21 with 29000 miles, the previous owner achieved a regional Top Flight with this car a few years back. The car is still original with two exceptions: the tires and the exhaust system. Previous owner found it necessary to replace the exhaust system from cat back. He replaced with "hideaway" style mufflers instead of the larger round ones and he also mentioned adding 2 1/2" exhaust pipes. I question whether this is correct or not.

When I look at the current catalogs (CC and Paragon, etc.) they indicate that both L-48 and L-82 got identical exhuast systems in '77. No oversizing for L-82 smog cars. I believe this is supported by the AIM as well. Here's the rub: the Judging Guide disagrees and indicates that the L-82 got 2 1/2" from the first horizontal connection back. Can anyone help me with this? I would like to achieve a Top Flight award under my ownership so I want to make it right but only want to buy pipes and mufflers once.

What is the correct pipe diameter and correct muffler type? Also, how serious a deduction for aluminized pipes as compared to carbon steel pipes? Do Top Flighters actually special order carbon steel? Who has the best exhaust systems with respect to NCRS standards?

[Harmon C.]

Re: Top Flight L-82 exhaust question

Mike
The way I see it the pipes start as 2" at the exhast manifold and are welded together at the Y to a 2 1/2" pipe that goes to the cat. I think this system was used for L-48 also. Most exhast systems will lose some points but are a very small part of the total to get a Top Flight and aluminized will not lose much more. Replacement tires of the same size and original brand will also get some points. If you drive to the meet you could make up for some of the deductions. Good Luck Lyle

[Joe L.]

Re: Top Flight L-82 exhaust question

Mike-----

The L48 and L-82 exhaust systems for 1977 were the same.