307 to 1972 350 ,big difference in performance ?
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More and more common, I am afraid. As said check it over and regasket. Word of warning, if it has the factory big dish pistons and shim head gaskets, you will lower compression even more. Felpro and most replacements are .040" or so thick, factory shim gaskets are .017" thick. It drops compression from 8 to 1 to 7.75 to 1, sucky. There is some light weight, modern ring pack pistons coming out in near future with a 8cc dish, 1mm top rings in 4.100" and 4.155" bore, perfect for early heads. The stock cam in that 350 blows, the early Vin 9 flat tappet 307 or 455 smog cam are an improvement but mild enough to not hurt bottom end on your 350. Unless the nylon cam gear was changed, that should definitely be done, those years tend to fall apart and get sucked into the oil pump pick up.
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Smitty sells .011 shim gaskets if needed (piston sits at least .027 in the hole) otherwise cometic goes .027 (I think?) on head gaskets. Cutting a few thou off the heads can bring back compression lost.
If you are going to replace pistons and do machine work, now we're in another world. There are enough options where a stock replacment piston with a 0 deck and a little head milling will achieve an acceptable compression ratio. Though, those new pistons will be a nice addition when they arrive.
If you are going to replace pistons and do machine work, now we're in another world. There are enough options where a stock replacment piston with a 0 deck and a little head milling will achieve an acceptable compression ratio. Though, those new pistons will be a nice addition when they arrive.
Rocket Racing sells a .028" composite head gasket. The shim gaskets from Smitty will work well with stock pistons but he has lost a step and his reputation has suffered with it.
I love the '72 350 I have in my Cutlass. I'm pretty sure its stock but it has plenty of power and more torque then I could hope for. Compared to the other GM engines we have had in the the family this rocket 350 has been a rock.
What a different world it would be if you could buy a new crate 350 Olds from GM.
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