348 heads on a 409 block

garys32

Member
just purchased a 1963 340HP 409 engine with a matched set of 348 1960 #3758379 heads. Can I run those heads on the 409? Is it possible to have larger valves and pocket port them to flow better? I also have a set of 333 heads, bare: which heads would be best to use. Engine will be going into a 1962 chevy impala with a 700R4 transmission. Car is a street cruiser, not a hot rod.
 
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427John

Well Known Member
The 333 heads with 2.06/1.72 valves installed will closely approximate the original correct heads for your 340hp engine,they will easily accept 2.19/1.72 valves and can be ported to support close to 500 hp.The 379's have already been a restriction for that 340hp motor.
 
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