If you look closely at that PSE and Victor 460, It may have my JDC on it somewhere. I did one for RJ several years ago, and it flowed so much air, that it was not very useful for most engines at the time. It even flowed more than the Dove spyder. A manifold only needs to be just big enough to supply the intake passage in the head all the air it can accomodate, and not pull it down, any--more will loose torque. Joe-JDC.
