340 Piston to valve clearance w/RHS heads

dodge freak said
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

The one thing that I noticed is you did not mention port velocity or low lift numbers,both essential in building an efficient engine.Those heads will have both those assets and make for a very responsive,powerful street engine.Add that with the superior combustion chamber and they are a far superior head-in fact by design they come out being the ultimate street head.The other thing is port size plays a bigger role in conjunction with cubic inch so a smaller engine could use less port size unless spinning higher rpm,a 340 to 273/318 is apples and oranges when comparing similar build up's