I’m going to call “foul” here.
First off...... it’s a BBC, not a SBM.
Secondly, that test is an RPM vs an RPM A/G.
The OP is asking about going from a std Performer to a Performer RPM.
On the right build, the difference in power between those two on a SBM could be pretty sizable.
The question is....... how much different will it be with the OP’s combo?
I wouldn’t expect too much.
We had a low CR 360 on the dyno here last year(not built by us).
SM heads that were checked out, rpm intake, headers, 750 Ede carb, XE268 cam, PRW 1.5 rockers.
Peak hp of 331@5200.
It was surprisingly low.
The intake and 750 didn’t work any magic with that one.
