At WOT the PI was pulling 1.0" of vacuum at 5000 RPM. The CJ was pulling 1.2", and the Performer RPM was pulling about 1.4". The 750 carb is definitely limiting HP output, because vacuum should be less than 1.0" for optimum power production. However, that's the carb that will be used in the car, so that's what we are using for all the comparisons.
I also have measured all the port openings on all the manifolds, and the PI ports are not that different from the CJ and Performer RPM port sizes. FWIW, I will be port matching all the intakes I test later this summer on my 428CJ to a medium riser gasket, since my 428CJ will be a little bit stronger build than this engine. However, in any case I don't believe that the PI intake would improve substantially with port matching to this engine, based on the vacuum data. In fact, if it did, again based on the vacuum data the other two intakes would improve more.
I'll provide more info in the final report - Jay
Jay Brown
1968 Shelby GT 500 Convertible, all aluminum 489" 1030 HP Supercharged FE
1969 XL Convertible, 460
1969 R code Mach 1, 706 HP 511" all aluminum FE, 10.457 @ 127.47, 2005 Drag Week Winner, Naturally Aspirated Big Block
