340 Piston to valve clearance w/RHS heads

goldduster318 said

Ok fine...but where's the quantifiable proof much you loose in an application like this? Engineering calcs? Dyno tests? Science it out for me if you're so worried about it.

Considering the old MM build where they used stock x heads with a good valve job, headers, comp xe 268, air gap, and a 750 edelbrock and got 391hp...with the heavy *** pistons. You guys make it sound like the difference would be 25-50hp in 400hp...when in reality I'm sure its well below that...probably closer to 5hp at high rpm.

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I just want to share this...I built an exact engine like that MM engine for a kid, who wanted good power. At the time, I didn't even know that build was done by a mag.
We used a 750 Holley, but everything else was the same....it made 358HP on our dyno. If I change the DTS dyno calibration to match Superflow, it would be about 374HP. Now every engine will make more or less HP even if built exactly the same but I thought the near 400HP was a bit of a stretch with stock heads.

You could mill .005 off the KB's and get the better piston too. Just a thought....