[Ironangel]

The 292 heads are a closed chambered head, the 781's are not. In stock form the 292's will have a higher compression ratio than 781's thus producing more power. I have a set of almost identical 290 heads on my .060" over 396 (408ci) with Speed Pro-L2240NF forged pistons. I'm inclined to agree with your machinist because a stock 402 piston with a mild 22cc dome will make some good low end power with 292 heads...Save the 781's for a future 600 HP build as they will out flow the closed chambered heads as they should because they are 454 heads. The 402 is a 396 bored .030" over so think of your motor as a 396 rather than a 454. The closed chambered heads kicked to the curb because they had inefficient burn characteristics, not because they didn't make extraordinary power. Most police and Super Sport applications had the 290, 291, or 292 heads because compression is power...