340 Piston to valve clearance w/RHS heads

Yeah and by using the lighter hypereutectic pistons, you'd reduce the piston weight by around 100 grams. So you'd reduce the rod/piston combo weight around 7% and the total rotating assembly weight (not including balancer & flywheel) by about 2%. I doubt that is going to make that much of a difference.

Forged pistons are really not the dinosaurs that you're making them out to be. Still the ultimate in durability. All the really serious stuff uses them for a reason, the modified turbo guys use 'em. Chances are you could have built it with cast pistons like were in my 340 when I got it...previous owner had it in a 71 Demon with a 4-speed and 4:10's that was a race car. Spun it to 6500 all the time...and those never blew either. Just because it didn't break doesn't mean that I want them.

My daily driver Chevy has hypereutectic pistons from the factory. more than anything I bet they use them in there for weight savings for fuel mileage. It also has a knock sensor. Hell it even has a 4" stroke and revs to 6300 rpm. They're very light because the compression distance is also short on it.

Anyway you crack it, stock stroke 340 pistons are all HEAVY. They have to be with the stroke and deck height the engine has.

There are faster cars than mine with 7 5/8" ring gears in the rearends (4th Gen GM F-bodies) that run 12's out of the factory, but I'll still use (and pay extra) for an 8 3/4 because I know it won't break. Same thing with the forged/hypereutectic piston debate. I'd rather pay more and KNOW I've got the most durable thing that I can buy inside of the engine. Build the rest of it high tech but strong and enjoy it forever. I'll bet I gain more power with the roller cam than I loose with the heavier pistons.

One thing from an engineering perspective about the large ring gap on the hypereutectic piston...large is saying that the top ring (same rings on any piston BTW) is going to run hotter than it normally would so there is room for expansion. To me, that says they get VERY hot and probably have a decreased life as a result. You have to remember that newer cars that use these pistons stock also have thinner rings and most are in aluminum blocks that dissipate heat better than our iron blocks...and have oil squirters directed at the bottom of the pistons. It seems very likely that they run tighter than 0.030 ring gaps too.

There's another thing that's bad that they still make: Professional Products intakes. I had an 89 318 roller engine destroyed by one 15 miles after i put it in. The casting was designed improperly and sprayed water all over the cam and also messed up the bearings badly.