If it helps I had the same fears of wanting a secondary electric pump when I put my Cummins in (not trusting / not wanting to trust the mechanical lift pump) and it actually did more damage than good, the engine ran a little weak (for what its worth!)... When I removed it, it was great. Not sure if that helps or not.
Second thought, the boost is way low... I don't think anything 'wrong' with it, just the way it is designed. But it is a direct inject engine, 10 psi is way way low, you can probably do 25-30 if you wanted to but about 15-20 psi is healthiest and most efficient and is a night and day difference (stock 4BTs are about 12psi max non wastegasted. Replacing the turbo really wakes up the engine, as if it had been slumbering its whole life, no loss in efficiency at all, in fact possibly increased. Just the way they did the logic around turbos back then. Mostly worried about higher EGTs from towing etc - which turbo out were bunk fears anyway). You could do a 4BD-2T turbo if it will work. But my advice is use something like a Cummins turbo if you can fit it, cheaper, just as if not more reliable, metric fittings, etc... Bill I'll pull out my HY-35 - it is massive, but smooth breathing and free flowing, works great in 3.9L diesel applications, wastegated, powerful.. But not sure if you want to get this "custom" as we;d have to make an adapter plate. But more turbo is absolutely awesome
Wastegated is nice but not necessary either, all it is is a blowoff, drops your high RPM boost from 20-25 to 15-20 depending on what you have it set at. So the turbo you choose does not necessarily have to be wastegated