what ya race with is diffrent than you drive
on the street harden seats vs non hardened
i to have run em too,, but, wouldnt waste my time ,for a street motor , 452 way better set, not prone to crack as 516 /906 and that maybe 1/2 point of compresion means almost nothin
for money spent to even make em good
if they are the only head , if the car was a restoration peice, had then i would

i do agree all heads being the same
you re car prob did run the same
so that proves that point / or 1/2 point of comp didnt help those 516 over come their realy bad flow either