All 940 versions use the LH 2.4 injection system, which doesn't need as sophisticated a distributor as the earlier LH 2.2 injection syatem, which have a Hall sensor within them.
LH 2.2 was used on 740 turbos until 1990, but LH 2.4 was used on NA 740s from year model 1989 on.
LH 2.4 dizzys are very simple, so they should be a lot cheaper to buy.