CPMotorworks Inc of Janesville, Wisconsin built 420ci SBC using SRH VFactor 2.50PF CNC heads. 11:1 CR, 237° @ .050" intake lobe hydraulic roller cam, CPM ported 2925 SV intake, QFT 4150 carb, 1.75" × 3.5" headers on VP MS109. 640hp/585lbs on 91 octane BP pump gas.