Cars » David's 421 Tri-Power

David shipped us his 421 block that we bored and stroked to 453 cu.ins. We used custom BP/ROSS dish pistons to achieve a pump gas friendly compression ratio using the # 670 D-port heads David provided, that we also ported & polished for better flow. We upgraded to an MSD ignition as well as a BP/Comp hydraulic roller cam and valve train for better power, drivability and durability. We topped this off with a completely restored Tri-power set-up that we dyno tuned to feed the new combo. David’s stock appearing but much improved 421 now make 490 HP and over 540 ft.lbs. of torque on pump gas! From David "We installed the 421 tripower in my 65 GTO this past week. It sure made a big big difference from my nearly stock 389 tripower. Boy it will move and quick."