Head chamber size..??

[Chevy454]

Not sure exactly what you have in mind, but I'd cc those heads to see where they're at NOW...the chambers are cast BIG from the factory, and if they've been milled quite a bit then they're going to be too small. Example: the chambers on our 840s were advertised at 107cc or whatever, but when I cc'ed them they were in the 112-113cc range...combine those big chambers, a good .038" Fel Pro gasket, and the stock 11:1 pistons, and you'll be right at 10:1 and can run an L72/L78 on pump gas! You can buy a cc kit from Summit or Jegs cheap...would be cheap insurance.