ProComp/Speedmaster aluminum heads

The SM heads are just copies of the Eddy’s...... and those have been around and used on enough builds to know what to expect.
From a tq/hp standpoint, especially in the 450-500hp range, I don’t think that there would be much difference between the two.

Especially with regards to a stroker, unless the OE heads are done pretty well(and yes, some are)....... I don’t see how the SM’s wouldn’t result in a step up in power...... even if it’s only a small step.

If someone has a decent set of reworked OE heads that have similar flow numbers to the SM heads...... then no, I doubt you’ll see any worthwhile gains.