I am surmising the sequence of what you did from your first post:
1) changed the MC and booster, retaining the stock 1986 calipers, and drove it around a while.
2) SAS and V6 calipers.
3) noticed a difference.
If that is the case, it makes perfect sense. The I4 calipers will engage mucho closer to the top of travel than the V6 calipers. With the V6 units, braking will occur closer to the floor but at the same point as a stock V6 truck. You could confirm that by driving one, and/or play with it by adjusting your pedal. Do not remove all freeplay, though. Brake fluid expands a tad and if you happen to put the MC piston too far into its travel at rest you could have some interesting experiences.