Question; if we go with a 421 vs the current 357, would the truck be any faster?
Currently my son has a 357 sbc in a S-10 extended cab which weighs 3800 lbs. We have 10.5;1 compression with Vic. Jr. heads which have been flowed to 300 cfm intake and 225 ex. We have a solid roller cam and roller rockers. The cam has .582 and .588 lift with 1.5 rockers but we have 1.6 and duration at .050 is 254 and 260. ( http://www.compcams.com/Technical/Se...umber=12-773-8 ) A Vic. Jr. intake port matched and a new Holley 780 Vac. sec. The tranny is a 700 R 4 and ford nine inch with 456 gears. MT ET’s are 26 inch by 10.5. The tires do not hook really well so the best we can get on the 60 foot is a 1.8x

His best N/A was a 12.9 @ 111 mph with his old carb, a 700 Holley. We haven’t had it to the track with the new carb but it runs a whole lot better with it. We thought it should have hit low 12's with the current set up.