i don't get the logic, you want high flowing heads yet aren't going to spin it past 6,000? A basic rebuild J heads with 2.02 intakes could flow past 6,500 rpm's. If your not going to spin it, you won't get the benefits of high flowing heads. Why the 273/318's came with small port heads, they flow BETTER at low flow demands. If the air moves too slow the fuel is going to drop out of the airstream and power goes down
Now the Chevy boy's do run .030 quench, so maybe it be fine but too close for my comfy leve
l. The old Mopar bible claim .060 was min.
Forged pistons are looser in the bore when the motor is cool and will rock more than hyper pistons. When the pistons rock the clearance goes down. Why the bible went for .060 clearance