Sir: I`m assuming that you wanna leave the crank+Rods/Pistons still in?, If that is so then you will be able to "Punch" the first 4 out and help them out of the crankcase - with the Pan off ofcourse.Putting new ones in will require someone underneth eyeballing when the cam bearing is centered in it`s bore.You`d be guessing though as to weather or not the oiling hole in each bearing is centered over the
oil pressure feed in the block.Still you will need to remove the radiator, and by the time you do all this - your gonna tell yourself that you would have been better off removing the engine and doing things properly...Good luck..Mike