Actually, there's almost no commonality between the Chevy 230 OHV six and the Pontiac 230 OHC six. The bearings and the bore spacing are about the only things that are the same; even the rods are different. Come to think of it, even the rear main bearing of the OHC is different than the OHV. There's an oil hole missing and a groove should be added for better oiling when you used OHV bearings in an OHC.

I guess the rod bearings are the same.

The Pontiac OHC rods are a much higher quality rod than the OHV. The forging and heat treating that went into them was different. MAny circle track racers used the Pontiac forged rod in place of the Chevy rod for their racing engines.

The flywheels are different, as are the balancers. The list goes on.

What is true about lower end commonality is that the Sprint version and the 1-Bbl version both used identical short blocks with the exception of the harmonic balancer. The 250 Sprint harmonic Balancer is hard to come by.

The main problem with the OHC is the cost of building one. For the same money, you can build a very streetable 455 with a lot more power and tons of torque. But - as mentioned - the curb appeal of an OHC car with the hood open is without compare.