Underpowered qd32 with td27t turbo

[Domdomforsure]

Hi all, I own a 1994 nissan datsun, it came with a td27t motor originally, but that seized, since then I've put a qd32 with a td27t turbo in, at first I realized it was sluggish compared to the previous motor. I realized the fuel had been turned down, so I've put it back up a small amount to about 850rpm. When I take it for a drive out on a long private road. I cant break 125kph, but my td27t would hit 140+ no struggles. And if I tow a 4meter load of wood up a hill I'd be in 4th gear easily holding 110kph in the old motor. This one on the same hill with only 2m of on the trailer, won't even get up past 80kph. Less wood and still sluggish? What are somethings I could begin to investigate on my own that might be the issue here. The previous owner was telling me how good the motor was and that it would sit 140kph piece of piss with a trailer but not as of yet ...this is a d21 body. D21 gearbox etc. But the engine is 1998 qd32 turbo. Any insight would be awesome as I don't really want to be having to turn the fuel up just to get the same power as the td27t. Thanks in advance