Piston Question

O yeah darn.....sorry, I forgot. As OldManMopar said, without the grooves inside the pin holes in the piston, then you could not use the rods made for floating pins unless you had the pin holes in the 526 pistons grooved for the locks at a machine shop... I have never priced out that work. Otherwise, you would have to change out rods. My son might have a set of the lighter rods for press fit.

One more thing to be aware of: Again assuming the heads are the Edelbrock 60779's: (Is your head PN in post #9 incomplete?) The heads have valves that are .24" larger in diameter than the original 318 valves. I suspect that the valve reliefs in the 285 pistons are too small to clear the larger Edelbrock valves. So you really NEED to partially assemble the cam and chain, time the cam, install one head, one set of valves and lifters, with light springs installed, along with the crank, bearings and one piston and rod set, and check the valve clearance.

JIMHO, and not to irritate you, but your low compression ratio and that moderately large cam are going to make the engine lacking in torque down at the lower RPM's. The engine is likely going to need to be spun pretty high in RPM.

I can't say on the NOS.....