if you have a 454 put a 4.250 crank shaft in it bore it to 0.60 this is a 496 good com a will make good torque and hp you will feel the torque before the hp and build the engine to the rpm you can use .if it is on the street you do not need 456 rear gear if you are driving on the hi way. srp pistons and scat crank is good stuff for the money the cam i would use a roller cam howards or isky the engine has a lot you do with what you do with the car i have had all big blocks in my 66 gto from 396 to 620+.and for the money some thing nice can be built for 6500.i have runed alot of coms I can help if you want getting 500hp is not hard but you will need good headers big tub at lest 2 or 2.1/8and exhaust 3 inch 3 1/2 with a x pipe and a good setup on the rear end to get it to hook try to get the car to take the power if not it will not hook