I haven't heard of anyone building a 434 stroker from a 396. You will need to zero deck the block, may as well get the pistons up as far in the hole as you can. This bottom end with the heads you have listed will only have a 9.5 compression ratio with the aluminum heads I would rather have about 10.5 compression ratio. I have a cam suggestion for you, it's a solid roller from Crower. Chevrolet Mechanical Roller Camshaft - Camshafts
. Talk it over with the old school racers and your machinist to see what they think. Try Mr. Gasket MLS .040 thick head gaskets. This way your quench will be on the money.