Common problem.... especially on race blocks, casting is too damn thin in that area. Usually safe to do that mod on a factory block, but not so much on race block. I dunno how many people I've had to walk through that repair on phone over the years.....

You don't need a $700 external pump to fix it... That is just an oil inlet for on block oil filter. You really should just switch to an external oil filter...... You are doing a W9 motor, you should not be using filter on side of block anyhow, you should be pumping oil into front R3 priority main oil feed.... I know, not as "clean & simple" as on block filter, but there is "clean & simple" & then the better way to do things.....

The filter thread inlet on block is 3/4" fine thread.... go to hardware store & buy a 1" UHL 3/4" fine bolt.... & you'll need to get a 1/2" NPT drill/tap, & a 3/8" NPT drill tap to do nice clean simple repair..... Enlarge the current 3/8" NPT hole in bellhousing area that was an access hole for that hole you just messed up to be machined.... it's in all SB Mopar blocks, & gets a 3/8" NPT plug normally..... well anyhow, enlarge that to 1/2" NPT to allow you room to access inside area with drill/3/8" NPT tap (might need a 3/8" NPT "extenson tap" like 4" long one is what I have.... & then just tap block internally to 3/8" & put a plug in there. So plug it there with sealer, & put sealer on 3/4" bolt & use it to plug the large center hole, don't worry about fixing hole in block & allow water to flow out into that now small oil passage that is plugged on both sides once you install bolt & the new 3/8" internal plug.....

Then drill/tap your oil pump outlet hole on side of block (lower of two holes on left side of filter boss) Put 3/8" NPT plug in upper hole just like normal, & then put an AN fitting out of the pump outlet hole, run line to your external filter boss (CV products makes nice one) & then pump oil put of filter mount & into priority oil feed @ front of block. Done..... no epoxy to worry about etc. Everything sealed up with NPT plugs & fine thread bolt with sealer. No leak, no worries & better oil system to boot VS using filter on block deal.