low compression

The 346 was basically 71 only from what I know, and had cracking issues because it was the first induction hardening. But, they are the head you're talking about with the combo of as-cast ports... they have a better height than the 452s, but the better exh port. I have a set I started porting. The intakes flow 285 @.550, exh 181 @ .550, 2.14/1.81, and I haven't done much of anything with the guide boss on the intake side. I only got one head done. the other's only partial but it's a great casting if you can find them.