[PontiacCrazy]

In A recent post I see people talking about exhaust being to small - ideally I would want to run the proper size exhaust to gain the most performance, correct?

I have A 1970 455 YH block, Edelbrock P4B intake, holley 750 vac sec, HEI w/man made lightning, Comp Cams 268H cam, stock valvetrain otherwise, 2k stall, 3:55 posi rear, 15 heads (4 exhaust bolt holes, not 6), all in 3880 pounds of car including me and 1/2 tank fuel.

Exhaust on the car is factory manifolds (1970 455 family car) w/2.25" dual out to the axle, with flowtech terminators at the end.

Good? Bad? Suggestion?

Thanks, Adam


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* No mister, it just looks like A GTO, but thanks. *

[PontiacCrazy]

In A recent post I see people talking about exhaust being to small - ideally I would want to run the proper size exhaust to gain the most performance, correct?

I have A 1970 455 YH block, Edelbrock P4B intake, holley 750 vac sec, HEI w/man made lightning, Comp Cams 268H cam, stock valvetrain otherwise, 2k stall, 3:55 posi rear, 15 heads (4 exhaust bolt holes, not 6), all in 3880 pounds of car including me and 1/2 tank fuel.

Exhaust on the car is factory manifolds (1970 455 family car) w/2.25" dual out to the axle, with flowtech terminators at the end.

Good? Bad? Suggestion?

Thanks, Adam


------------------
* No mister, it just looks like A GTO, but thanks. *

[Jim Hand]

Adam,
Your exhaust system size is a good match for the equipment you are running. The outlet openings of the stock manifolds are between 2" and 2 1/4", and the exhaust pipes are relatively straight with minimum bends, so there is no reason to have larger pipes/mufflers. When you do decide to replace/upgrade the stock type system, a small power gain might be realized by opening the manifold outlets to about 2 1/2" and substituting 2 1/2" pipes/mufflers. However, the power gain would be quite small and not worth changing unless the present system is worn/leaking. If you ever switch to headers, or the cast Pontiac style header/manifolds, a 2 1/2" system through the mufflers would assure maximum power. How do you like the sound of the Terminator mufflers? We found them to be very authoritative sounding! Jim Hand

[PontiacCrazy]

The terminators are actually relatively quiet.. But as i've noticed with other mufflers i've used in the past, they get a lot louder above 2500 rpm (most of my street cruising is 18-2200) so you don't hear much unless you intend to.

When you do intend to, a lot of heads turn and wonder what the sound is. lots of compliments. (my 2.25" setup sounds as healthy as A friend of mine's 3" flowmaster setup.)



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* No mister, it just looks like A GTO, but thanks. *