Originally Posted by 55_327
I love the Street Warrior on my 327. It's a much newer design than the Performer or even the Performer EPS. And the rear vacuum port clears Holley float bowls.
That single plane manifold is hurting your power at RPMs up to 4500 or even higher. The problem is all 8 intake valves are exposed to each other. That means, for example, while piston #1 is half way down the intake stroke, cylinder #8's intake and exhaust valves are both open (during overlap). This means some of cylinder #8's exhaust gasses are sucked through the intake plenum and into cylinder #1. And this is repeated on every intake stroke of every cylinder. The larger the cam, the more the overlap, the bigger the problem -- at least at low-mid RPMs.
You might want to read the RPM range as posted here http://www.holley.com/data/Products/Technical/W504.pdf
This manifold is almost mandatory by some stock car rule books,it takes torque to pull off the corners on an oval track and the 7546 will deliver the goods.