Cylinder Heads

[Sgt Art]

I know where I can get a set of "C" casting cylinder heads for a 455 Olds engine. These heads were made in 1968, do they need hardened valve seats? TIA.

[rocketraider]

Depends on how you're gonna use them. For a cruiser or lazy street driver, you can probably get away with not installing hardened seats and using octane booster or lead substitute, or even some 100+ octane racing gas once in a while, and they'll survive fine.

If you're planning to use a 455 like it was meant to be driven, I'd say yes, have them installed. Just make sure your machinist uses the ones for an OLDS engine, and not big-block Chevy. I've seen Olds heads ruined by trying to put in the BBC stuff because the machinist cut into the coolant passages. If that happens, you've got a pair of C-casting boat anchors, and an argument with yer machine shop.

Are these big-valve (2.07 intake) or small-valve (2.00) Cs? Good set of heads either way, but the 2.07 are the factory hi-po pieces, used on 67-69 442 and Toronado engines. I've also seen them on factory dual-exhaust 98s. Unfortunately no way to tell with them on the engine- no difference in casting #s between the two.

[Sgt Art]

I spoke with a machinist friend who confirmed what you've posted. He said the exhaust valve seat area would be is if they were hit with a ball peen hammer. He said he'd show me a set where the area set back almost 1/4 of an inch. He went on to say that short trip driving probably wouldn't be a problem, but long term would be. I don't know if they are large or small valve, I need to ask the seller. He simply said they were cleaned, shot peened, and crack free. They're off the engine, and I'm certain he can tell me. I'm betting they're the 2.000 valves as he didn't mention the size but states they are rumored to be the best flowing Olds heads.