Jim has the right idea. Tighten up the converter,lower the RPM and let it grunt. Obviously not as good as a better set of heads. You've got to work with what you have. We'll see, I have Jims old short block that Im going to run in N/SS. At 3300-3400lbs you need all the torque you can get. I have a set of hand ported heads by MCH who also did Jims. Not sure which set was better. I'm running more compression,slightly longer cam with wider lobe centers,not to mention the Indy crossram and carters which certainly is not as good.
There is light at the end of the tunnel though. Some of these 572 combos have run pretty well. Nick Wilsons is impressive running SR heads,9.30s@3700+ lbs
Doug