With a little bit of work you can get really great performance out of these heads.I know i guy who runs a mildly worked set on a full interior 74 camaro that has a pump gas 496 running a flat tappet solid cam. Race weight is about 3500 lbs and he runs low to mid 6 seconds in the 1/8. You might be better off spending a little $ on what heads you already got than alot of$ buying new heads. Word of advice the rocker bosses tend to crack under high spring pressures/rpms. A little cash will get them welded up around the bosses for strength and they will hold up fine after that. Seen it done alot with 100% success. Good luck!