My block is a ribbed service replacement 428 the lifter galleys were tapped for 1/4" ipt plugs all I had to do is tap 1/8" ipt threads down below the outer plugs and install 1/8 inch plugs (shorties) and reinstall the outer ones, also this block had been opened to 7/16 at the
oil adapter, along with mods to the main and cam bearing
oil holes they seem to have been slotted for better alignment, the block has the triple webbing just like the cj and the
oil mods look to be factory done or at least by a machine process. I also tapped the rocker shaft oil feed holes and used screw in .090 oil restricters 1/8 ipt. Melling M57B standard volume 428 oil pump. Standard 428 front sump pan and a 427 oil pickup tube with the larger diameter tube and center pickup. 428 scj oil cooler adapter.