Enlarging PRP doesn't always help

PRH said
With that engine, the car has gone 10.80@123, at 3250lbs.
I won’t give too much away, but the peak intake flow of the heads is 200cfm.
You can use your favorite performance calculator to figure the HP.

Apologies for the thread sidetrack.

Not a sidetrack at all. Many of those stock class heads are the perfect example of what we're discussing.