[74Grandville]

I have a 79 T/A and i'm trying to deside what size exhaust to get.

I have a 462

#62 heads lightly ported
KB pistons 9.5-1 compression
stock 44bl intake
44bl Quadrajet
cam close to 068 with 1.65 roler tip
hedman 1 3/4 headers

This engine will be a strickly street use car.

I would like good air flow, but don't want to hurt my back pressure.

Will 2.5 be enough? I was thinking 3" because of a chart p-dude has on this website.

[74Grandville]

I have a 79 T/A and i'm trying to deside what size exhaust to get.

I have a 462

#62 heads lightly ported
KB pistons 9.5-1 compression
stock 44bl intake
44bl Quadrajet
cam close to 068 with 1.65 roler tip
hedman 1 3/4 headers

This engine will be a strickly street use car.

I would like good air flow, but don't want to hurt my back pressure.

Will 2.5 be enough? I was thinking 3" because of a chart p-dude has on this website.

[74Grandville]

Also. Is it worth getting an X or H pipe?

more specs

M21 transmission
3.42 gears
255/60/15 tires

[Fox]

H pipes are cheap and worth the trouble. X pipes are more expensive and more difficult to fit in an existing exhaust system so you need to be sure you really need one. I have a feeling that on a mildly tuned 400 or a relatively stock 455 engine that it doesn't make much of a difference.

[Bartman]

I'd stay with 2.5 with how mild your combo is unless you want a real deep rumble. You probably wouldn't see any perforance gains 3" but it does sound real cool. Also an H or X pipe can quiet your exhuast some if it ends up being louder than your neighbors want.
Bartman

Ponies run but Birds fly

[Sixties Guy]

A properly designed 3" system with X pipe shouldn't hurt your backpressure, plus you'll be ready if or when you want to do some upgrades to your 462.
I have a 3" system with X pipe on my basically stock HO 400 '67 GTO and have experienced no downside. I am currently using the HO manifolds with 2.5" downpipes tapered to the 3" headpipes. This system was installed in anticipation of a moderately built 462 going in at a later date.
All tests I have seen have shown the X-pipe making more power than the H-pipe and it does quieten it down some. As stated above though, it will be more difficult to fit on a system already in place.

[Bob with the 66]

Sixties Guy,

Your the first person Ive heard that did not say that 3" was overkill for a street car. I put full 3" on my 66 with a cross over and 2" headers (467) and alway's wondered if I made a mistake. I never ran the car with anything else so I couldn't tell if it was helping or hurting me.

I'm glad to hear your opinions,they answer just one more of the many questions I have.

All good things are worth waiting for. "Yeah right", I want them now!

"Artificial intelligence is no match for natural stupidity".

[Bob with the 66]

Sorry, I ment x-pipe not cross over.

me bad

All good things are worth waiting for. "Yeah right", I want them now!

"Artificial intelligence is no match for natural stupidity".

[Sixties Guy]

Bob,
My system was purchased from the Buick GS Club and was specially made for them by Hedman. Of course it will fit all GM A-Bodies so it worked well on the GTO. The club newsletter was filled with positive feedback on the system so after a few months of reading about them, I ordered one and have been well pleased. As stated earlier, I have a basically stock 400 HO with 4 spd. and 3:23 gear. I can still lug down in 4th gear, don't have to downshift to pass, just kick in the secondaries and go. I am running 2.5" outlet HO manifolds and 2.5" downpipes tapered to 3" headpipes. Am also running DynoMax Ultra-Flo Welded mufflers.
I firmly believe the x-pipe and Pontiac's traditional torque output are the major factors in keeping the 3" system a viable street option.

[74Grandville]

I'm thinking i'll go with the 3" with an X Pipe. I know this might be a little much, but I do plan on upgrading in the future and I don't see how it could hurt me either. I'm still thinking about it.

Thanks for all the replies!