If your going to bore a 305/350 and buy pistons,cam and valves you blew the budget unless you own the machine shop. Buy a new 350 from GM. Dont use claimer motor parts. Cheap stuff because of the rules and not very good street parts. I dont know how you could win with a 305 claimer motor on dirt or pavement .IMCA ,FASCAR or? there are some real big motors in those claimer classes or are you stuck with the 305?. We do have one class that you have to use the 305 but they cheat those pretty good. Our claimer motor is and old 358 dry sump motor with a wet pan on it.Aluimn heads painted Bring that 305 on LOL 14 wins last year with 1 motor.
But seriously the 350 from chevy is 1300 bucks and it is brand new with a warranty Jasper aint all that bad either but rebuilt.4% failure rate.
