I checked the cast# on my heads 343772 truck heads. How good or bad will these be on a street motor pump gas and 5000-5500 rpm limit?
Thanks Dave Seitz

Don't think there are really any bad bb heads at 5000 to 5500rpm's unless the little -236 peanut port ones come to mind... But I would steer clear of rectangular ports in that rpm range regardless... pdq67

Thanks for the info I'll get these redone and put them on.