I know it has been posted before, but could not find it in the search?

What block modifications are needed for 600-650 HP, 6,000-6,500 RPM?
Street/Strip 440 to 505" stroker. Trick Flow 240 heads, 10.0:1 compression, small solid roller cam (243/249@0.050", 0.617"/0.624" lift.)

Would this be OK with 3/8" oil pickup, or just go with 1/2" pickup.
Ream main oil feed holes to 17/64"?
anything else?

I use the Seal Power truck narrow full groove main bearings, either part # M4500 or 4500M part number for RB motors, and I do groove the #4 cam journal on all my solid roller cam motors to lube the rocker arms full time for cooling the valve springs, I use a .039 to .053 oil resrictors in the head or block, your choice, also to not flood the top end
I shoot for between .0030 to .0040 main bearing oil clearances and between .0025 to .0030 on the rod bearings clearances, way better a little loose than a tiny bit to tight on BB Mopar bearings
As far as any other mechanical oil mods to the block I thoroughly remove all the casting flashes inside and out I don't recommend changing the oil tube size from 3/8 NPT to 1/2 NPT I always use the high volume oil pumps with as big as a oil pan that I can run safely on that body for all my BB engine builds, even mild ones
What year and type body is this motor going into?

This will be going into a 1966 Plymouth Fury C-Body. Not sure if a B-Body hemi type oil pan will fit? On my other engines I did the 1/2" pickup modification, but had problems finding oil pan pickups. On the Charger with the BCR girdle, I ended up making my own oil pickup tube to fit the low profile Milodon oil pan.

I did find some links to the old posts using a Google search.

I think Hughes has some mods on their site & you might Google it. If you go to www.moparchat.com then scroll down to & click on "circle track chat" there is an oiling sticky at the top of the page: "Sanborns oiling mods". it is SB orientated but alot bleeds over. it'll take you several hours to absorb it all but it is worth it. this was my last one. (screen added later) EDIT & I reduced the protrusion

What is needed - Probably nothing, IMO.

That said, I cannot leave it alone. I massage the inside radius of first right angle encountered in the block on the suction side. Clean, radius an enlarge everything in the pump including the oil filter fitting. I've posted before the significant misalignment in the Melling pumps between the pump body and pump cover on several pumps. Probably a 25-30% crossection reduction due to the misalignment between the two pump halves. Hopefully they fixed it, but you should check.

Then radius and enlarge the the pump and block pressure side transition.

If the hemi pan fits, use it with either pickup you want. I use 1/2", May not in the future. Slight mod of the 1/2" and it worked fine. Full length, std stroke Milidon standard stroke windage tray, inexpensive girdle, scraper, and it all tucks up real nice.

I use a standard volume pump, full time unrestricted rocker oiling, with 0.003/0.0025" bearing clearances and have good oil pressure.

I'll bet money that the 1966 to 1969 Hemi oil pan will work well in your C body, those two oil pans are almost identical looking compared side by side
I've used the those early year (1965 to 1970) C body oil pans after welding in slosh and acceleration baffles in early, pre 1966 B bodies with good results after the stock street hemi pans got to expensive and to hard to find back in SO CA in the mid to late 1980s

that's the story of my life!

Got around to working on the block oiling.
Opened the 1,2,3,5 main feeds to 17/64", and #4 to 9/32"
These are the sizes suggested from Chuck Senatores' book.

Andy Finkbeiner suggests 1,2,3,5 be 9/32", and #4 be 5/16". I don't think I need to go that large?

I did open up and tap the oil pickup boss for 1/2" oil pickup.

I also made sure the pressure side from pump to cross and main lifter galley were 9/16".

All other feeds to cam bearings and head/rocker gear are 1/4".