I am doing a 4.0 head conversion and my 1983 258 (4.2L) engine uses 7/16 inch bolts. The 4.0 head uses 1/2 inch bolts. Does anyone know where I can purchase 7/16 head bolts with sleeves to fit in 4.0 head conversion? Or do you know if the engine block can be machined to 1/2 inch holes while the engine is still in the Jeep?

78 CJ7, 83 wide track axles/Dana 30 Front W/ OX Locker, Model 20 rear w/ one piece shafts(welded tubes)/Detroit Locker, 4.10 gears. 4.5" spring lift with 3/4" shackle lift. 35x12.50 BFG MT, 4.2L, Weber Carb, K&N, T18,Scout Dana 300,Warn 9.5ti