[chiphead]

I will never again dump a lot of money into iron heads. At least for me, it's impossible to find a machine shop that will rebuild and port a set of iron heads properly. I ended up with over half the cost of aluminum heads in these 670s. Not to mention it took 9 months to have them ported and rebuilt. After a local shop screwed them up, I had to source my own valves/springs/retainers/locks, drive 2.5 hours each way to Charlotte NC to bring my heads to Marty Warden for finish work and porting. The results are awesome, but it's still a 260CFM iron head. For not much more, I could have had 290CFM aluminum.

So if I had to do it over, I'd go straight to aluminum. So for your build, go with a set of 72cc aluminum heads and whatever piston will give you 10.5 compression with whatever stroke you end up with.

UNLESS.... You're building the bottom end now, go with the 4" stroke crank. Find a set of 80-84CC iron heads to use until you can afford the 72CC aluminum. That's what I did. I built a 434 with a 10CC dished piston. My 80CC 670s give 9.75 compression until I graduate to 72cc aluminum. Then the compression goes to 10.5 and I make more power everywhere.