Try a little stiffer throttle return spring. Keep working on it your getting there. P. S. my 770 VC Brawler already had everything drill and threaded. The one you have must be much older. The only thing I had to fix was the IFR, of course because these manufacturers just insist on the upper...
6.5 -7 in my opinion way to high. It's not pressure you want it's volume. 5PSI is plenty. You want the fuel going into the bowl like a garden hose flow not spraying in.
Sounds like the needle and seat needs replaced.
That engine builder [Jim] from Idaho proved you can can make good power with a motor home 440. There is a long thread out there where he did dyno testing. Get a set of heads, spec a camshaft,SD intake, headers and run it.
This. Because he's your brother is more reason to knock his a__ out. He only does it because he knows your not going to. Does he berate other people? Probably not because he knows he might take a beating.
Or ignore him and block him from your life. Don't just take his crap.
I used a factory style windage tray and an old Moroso pan on my 512 with no clearance issues. 7 qrts + 1 in filter. Upper 10's is double with 3.55 gears and a stroker BB. My sbc with 3.42 gears and 2500 convertor has run 10.86 @ 125.6. sbc stroker. 3570 with driver.