366/396/402/427internal balance from gm all 454 are external balance so you need one for a 454 the race stuff alot of times go internal but you can not just throw a internal bal on it and call it good takes heavy metal in the crank or a after market crank made for a internal bal you can use a stock type will work but you may what a SFI secifications and there are good bal like power force+plus power bond . better ati tci fluidampr any one of them would work to but are a bit more money i like the ati.