Aluminum Hemi Indy Maxx block HELP

I recently picked up a never used older aluminum Hemi Indy block with 4.5 bore. I have read many stories on older threads about oil return issues with these blocks. I have tried many times calling Indy about their input on modifications needed to fix the oil return issue from the heads and valley, but nobody ever answers the phone and voice mail is always full. Not good PR. So, I am turning to the Moparts guys for input before I continue with the build. I have read on here to open the valley holes to 5/8 diameter or machine slots similar to stock blocks, along with opening area for drainage to timing chain area to allow increased oil return to pan. Also, recommended increase head oil return holes in block, but to what size? Currently 5/16 in diameter. Right front head oil return is a blind hole with tapped hole at top and bottom of block. Does this need to be increased for larger external return line? Any help or advice on necessary mods to the Indy block would be apppreciated. The heads being used are Edelbrocks Victor Jr's. I'm sure many of you have experience with these earlier blocks. Thank you. Gary

I drilled the block deck corner holes out to 3/8" because that's what someone told me to do. Stock street hemi is 7/16", KB is 1/2" but I didn't want to drill bigger than I was told for obvious reasons. I can't tell you all the hassles I had out of that block. Russ was the biggest POS that ever lived.

I purchase one of their newer blocks and was told to drill out the oil drain back in the lifter valley double of what was cast(1/2') and drill a hole in what is called a China wall for better drain back hope this help.

You might (also) try posting on Don Terrill's Speed Talk website in the "Engine Tech" forum where many engine builders and engine machine shops post and respond to questions.

https://www.speed-talk.com/forum

He is a photo of the 1" hole in the china wall and the opened up lifter valley holes I did in the response to advise from Todd Marsh and others. Without these mods (and the deck mods) the engine ran out of oil in 45 seconds after startup with oil pouring out around around all the lower valve cover bolt holes. This was after spending a day trying to get the engine in the car. I had 3 brands of starters. None would fit the block. A lot of time was spent grinding and trying different starters. By the way, the engine sat crooked in the car. I worked a month on that. (Never did get it straight.) I can't say enough bad things about Russ.

Hopeful all the issues were address with the newer blocks ,first time hearing all the fitment issues

Right side of block for external line.

Wow, I'm having a little trouble understanding that. Can you back up a little for a photo? What is the other side like?

Here is front of block, right side requires external oil return.

I didn't know they had made that change. Sorry.