Pro Comp heads
I have had customers bring them in and we have used them.
We had a sbc set that went 9.0's and 160 in the 1/4
I have used the 320's as well.
I have another build friend and he get about 980hp ish out of them, NA.
I would want to look at them first.
320 are big for a small bbc...
Good Luck.