I bought a 92 S10 and the 2.5 was practically gone and i replaced it with another 2.5. It to was knocking, So now I've bought a 91 Chevy astro complete with motor (4.3) and all. I'm looking for any info on the wiring and fuel injection matching up or if I have to cut and splice everything and pt a carb on it. My questions are all about the fuel injection and the computer wiring. what all has to be changed? Any info on this project would be greatly appreciated.

You'll need the following to move the 4.3 into your 2.5 s10

Engine
Engine harness for your year blazer and matching ECM
All associated sensors for that year
All accessories
Misc parts that are different from the astro and blazer (rad, coolant recover tank, stuff like that)
DRAC unit

fuel pump, dont forget that bugger... DRAC unit?

fuel pump, dont forget that bugger... DRAC unit?

The drac converts analog signals (such as signals from the VSS) to the ECM. Also it has rear gear ratio and tire size info built into the chip.

ok, your talken the chip on the back of the cluster then right

ok, your talken the chip on the back of the cluster then right

No, the DRAC is the box attached to the ECM

what about going the other way, I have a 91 4.3 liter v6 187k miles, I want to drop in a smaller moter to save on gas, it will be for my son, back and forth to college. Is there any motor that will fit that one? The one I have is burning oil, valves and rings are hosed.

to go down from a 4.3 to a 2.8 or 2.2, you would need those moters pcm, wiring, fuel pump, and accesories

what about the tranny, 60 degree to a 90 degree?