ATK 5.9 Magnum crate motor horse power

@rumblefish360 - Yes, to your point a cracked Magnum head can run a pretty long time without even being able to tell (and may take a while to even crack in the first place). But over time that crack gets worse (i.e. coolant starts to leak in, etc). The head replacement rate in the field on 318 / 360 Magnums is quite high. There's a reason there are 3-4 companies making regular replacement heads for them. The point is, why would you buy a crate motor with crack-prone heads, even if it would take ~30-60k miles to manifest itself? Or even if there's "only" a 25% chance it happens? It's too much money to risk it.

I agree with you: aluminum all the way! Just save up and do it right.