70 heads on a 74 block?

any issues with the running the earlier heads on the later year block?

 

You shouldn't have any problems. They're basically all the same except the '70 heads give more compression.

Rob

 

I know with the 455's - going with older heads on newer blocks is OK. Not sure if that rule holds true with the 350. I don't think it's a problem.

 

It's no problem.
The only kind of heads to worry about are 68 and 69, whick are oil through the head, instead of through the pushrod.

70 thru 80 are interchangeable.