The torque curve on these is pretty good, plus the weight is a factor. Having said that I wouldn't do it, since the amount of custom fab work required is pretty high compared to something like a Chevy 350. The benefit just wouldn't be worth the development effort.
As for ECM work I ass-u-me he used the one from the donor, but then the next question is if he also used the BCM, and what did he do about all the other stuff (gauges etc). It's a trail boat so he probably skipped on all that. Or maybe he used a stock GM throttle body and FI controller, those are widely available but then issues with ISC management, etc., and its not a 350, so ... I dunno.
Discussion board posts say change the TBI and injectors, and the Trooper computer works. Early gen Troopers apparently used GM TBI engines same as the S-10 Blazer. Dunno how they get around the ignition.
Automobile(s): 1987 Pontiac Fiero GT with built flat-tappet Northstar
Re: 4.5 in an Isuzu Trooper
7730 computer from a multitude of GM applications, including '90-'92 Transmarobirds can be retuned to run a PFI 4.5/4.9, especially if using a throttle body from a TPI or LT1 engine.
The TBI engines can be run by almost any OBDI computer GM made.