[1967Tempest]

Im curious why they cut out the center on one side and not the other.

[242177P]

Originally Posted by 1967Tempest

Im curious why they cut out the center on one side and not the other.

If you study the firing order, the driver's side has two consecutive fires, 5 and 7. Five (center) absolutely has to get out of there before seven (rear). Could be the reason it has a center outlet? On the passenger side the exhaust exits in a more orderly fashion. The only thing that comes remotely close is four and six (both center) but there's a pause while three does it's thing.

But wait! There's more! (there always is) Let's not forget about the exhaust crossover. When that flapper is closed, the passenger side's center is now the exit. Forget what I said about orderly. Everybody on that side is now trying to exit through the intake manifold. And you've seen the size of that exit. Can you say gridlock? Hey, let's knock out that wall!

I'm sure that only scratched the surface, and I could even be wrong.

[KSZR]

I've got a 72 Lemans I've had for 30 years. It was my high school project. It's got a 400 bored 30 over, #16 heads, 068 cam, cast iron manifold with Q jet with dual snorkel, log manifolds and 2.25 crush bent exhaust with quiet mufflers. HO racing carb and distributor kits.

Running a fresh 200-4R transmission and 12 bolt 3.55 rear end.

With my dragy my best 1/4 mile run is 14.59 at 96 mph. Thought it would be better.

Always wanted to do the ram air manifolds but then I saw this post!

How much performance gain would I get with the log manifolds opened up to 2" and a pypes 2.5" mandrel system?

VS what I have now?

VS ram air maniolds and pypes 2.5" mandrel system?

Thanks! Kent Kelsey

[Ccass]

Originally Posted by KSZR

I've got a 72 Lemans I've had for 30 years. It was my high school project. It's got a 400 bored 30 over, #16 heads, 068 cam, cast iron manifold with Q jet with dual snorkel, log manifolds and 2.25 crush bent exhaust with quiet mufflers. HO racing carb and distributor kits.

Running a fresh 200-4R transmission and 12 bolt 3.55 rear end.

With my dragy my best 1/4 mile run is 14.59 at 96 mph. Thought it would be better.

Always wanted to do the ram air manifolds but then I saw this post!

How much performance gain would I get with the log manifolds opened up to 2" and a pypes 2.5" mandrel system?

VS what I have now?

VS ram air maniolds and pypes 2.5" mandrel system?

Thanks! Kent Kelsey

vs a crimp bent 2.25" you should drop a 1/2 second in the quarter mile. I don't think hogging out the end of the manifold flange will affect performance that much.

[KSZR]

Originally Posted by Ccass

vs a crimp bent 2.25" you should drop a 1/2 second in the quarter mile. I don't think hogging out the end of the manifold flange will affect performance that much.

Awesome thanks! Any opinion on what the ram air manifolds would add to that?

[Ccass]

Originally Posted by KSZR

Awesome thanks! Any opinion on what the ram air manifolds would add to that?

maybe another 1/10-2/10 if they were port matched and polished? The big question is finding a pair. They are out of production now. The whole Pontiac industry has been out for a while. So they are really hard to find.

[KSZR]

Originally Posted by Ccass

maybe another 1/10-2/10 if they were port matched and polished? The big question is finding a pair. They are out of production now. The whole Pontiac industry has been out for a while. So they are really hard to find.

OK didn't realize that. I guess makes the decision easier and can always upgrade if they become available (along with the different head pipes).

Which Pypes muffler, turbo pro 14" or 18"?