Not to jump out in front of Rob, but that makes sense to me. The '86 and earlier Troopers had a crossmember further forward than their later brethren, it's one of the quirks that makes them less friendly to larger tires since it intrudes in the front wheel well. As the C223 engines were put in those earlier Troopers, and the 4JB1 was developed for the later series, with the different crossmember, it would be more likely to match up with your '88 set-up. Naturally, either could be put in the truck, but it may make a difference in whether you had to fabricate/relocate a crossmember.

(BTW, good to see you around Rob)

James