Rpm vs stock intake
 

A couple of differences were asked in another thread. I did this a while ago just for s&g.


Rpm is 1" higher at rear carb mounting holes
Rpm is 1 3/16" higher at front holes.
Rpm carb pad slopes towards the front 3*.
Stock carb pad slopes towards the front 6*.
Rpm carb mounts 5/8" rearward from stock.
Stock plenum depths are 3 1/2" and 1 7/8"
Rpm plenum depths are 4 3/8" and 2 3/8".
Rpm plenum depth difference is 3/8" more than stock.
I did not measure ports sizes.

The Edelbrock catalog states the Performer RPM port exit dimensions are 1.100" x 2.060"

My records state the H-O book says the stock ports are 2.05" x 1.130"

I don't recall the source but my records have the RAIV at 2.180" x 1.160" and the 455SD at 2.220" x 1.180"

Jim Hand lists the stock iron and aluminium HO intake with average runner length at 5.21" and the Performer RPM with 6.28"