Speedmaster Small block porting tips and results Part 1

pittsburghracer said
I think it was 318 that gave me his throat sizing on his cnc’d heads and it was a lot bigger than my bare heads. .

PRH said
I have some cnc heads here.
The throat is flat out too big for the 2.02 valve at 1.890(93.5%).
That’s a big part of why the mid-lift numbers with those heads aren’t great(frankly, with the ootb vj the low/mid-lift numbers are rather poor).

They cnc the bowl right to the 45.

View attachment 1715445145

My heads were not CNC'd. I bought the regular SM heads fully loaded. I think the bowl and throat are big for 2.02's as they are, so I agree with PRH that the CNC ported heads would be best with larger valves and better valve job