I'm trying to do unported and port matched versions of the higher performance intakes. So, for the Performer RPM and the Streetmaster, I have both unported and port matched data. For the Performer and the SP2P, I don't think that port matching would make a big difference because they are kind of low on the totem pole anyway, so I'm not going to bother with port matching those manifolds. I plan to port match the F427 and PI and retest them soon, and the BT is already set up for the CJ intake ports, so no port matching is required.
I've been using 3 carb spacers for all the tests: 1/2" 4 hole, 1/2" open, and 1" open. So far with the intakes I've tested, the effect of the 1/2" open and 1" open have been about the same (see Report #1).
The low speed characteristics of the RPM are kind of strange, and they don't make a lot of sense to me. All I can say for sure is that on this engine, they are repeatable. There may be differences on other engines, of course.
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
