I had a 429/C6 in my 69 galaxie XL/GT. I put a 351 W into my 69 coupe. Altho the rebuilt 351 doesnt have quite the pull of the 429 I cant imagine wanting more than what you can get out of a smaller 351 block. The weight of that monster is a disadvantage, you will loose knuckles trying to pull a plug. Think smart and serious before you open your wallet. Stan