i have a 77 with a 20r and i want to put a little louder(dumb) and less restrictive muffler and larger pipe from the cat back, they have at pep boys an aftermarket can that looks stock and is pressed at the seams for 30 bucks...the atendent said it would be louder than stock but not like one of thoughs fart cans, this is what i want. they range in size from 1.5 to 3"...i was thinking of geting a 2 or 2.25" but what do you guys think? i dont remeber the brand was but what and were should i look for value and a deeper sound/less restriction?

 

If your engine is stock only do a 2" system or you will lose too much back pressure.

 

i figured...2" it is. what if i were to get weber?

 

Even with the weber i mean for more then 2" you would have to do head work and maybe even more.

 

What is back pressure?

 

Back pressure is when the exhaust gases back up back into the cylinders from the exhaust system. most cars from the factory have a little too much. Now getting rid of back pressure is a good thing but with are stock even lightly modded motors going more then a 2" exhaust will cause us to lose too much back pressure. Some people say its good to lose it all but then then fuel isn't all burned before it passes through the cylinders into the exhaust system. Therefore a certain amount of exhaust back pressure is needed to prevent unburned fuel/air mixture from passing right through the cylinders into the exhaust

 

Oh ok, yeah ive heard of people saying not to worry about backpressure becuase the engines are so small. Glad you could explain it in simpler terms.

 

your 77 has a cat? Mine was catless from the factory and even had the sticker in the door jamb to prove it haha, I did 2 1/4 pipe from the header back to a Flowmaster and loved the way it sounded. No ricer but quiet a bit louder than stock, did the same on my 83 WITH a cat and it just doesnt sound as good to me