Thanks, Mike

I do believe( don't hold me to this if i get it wrong) it came in the late eightie and early 90's S-10 pickups and brethren

The S10/S15 never had the 3.1L. The 4.3L replaced the 2.8L before the engine was enlarged.

So get the same drivetrain for the 2.8 and use GM performance parts 3.4 L replacement engine