[2manyT/A'S]

Originally Posted by Zirconia

I swapped out a set of RAIII Manifolds on a 73 455 automatic and gained a tenth of a second! Not statistically significant. You can get more of a power boost (up to three tenths) by cooler ambient air.
In box stock form breathing through the single catalytic converter, a W72 should, seat of the pants, feel no more than a tic slower than a RAIII. Check out the first car, a box stock Martinique Blue 78 W72 in my Movie This car has the original pellet style single cat:

http://www.youtube.com/watch?v=aLf5a5gejUI

Enjoyed your vid... The 78 does pull pretty strong,what RPM were you shifting at?
(sound like you might have short shifted into 3rd a few times}