Alloy heads

He everyones right about something
YR when he talks about combustion chamber and spark plug location (and quench and piston etc)
Easy test- how much advance required
Magnum and late LA motors are way better than early Iron (IDK about closed chamber 273)
even EArly LA iron with high quench pistons
I've got lots of dyno time on those early heads many years ago
new heads are much better
now al vs Detroit wonder metal- it's all in the details of the build
you can always build something that will detonate and detonation will kill any build