[Ryann627]

I’m planning to buy another 4.3l v6 non-vortec for my 91 s10. I’m going to put a new cam, pistons, connecting rods and a TorqMaster SuperCharger since all the bolt patterns are the same. Maybe 50 shot of NOS in the future.

How do I make sure the new engine is the same as the old engine? Meaning that it came from the same plant and year so I know the computer mapping is the same?

And I know a 350 is better. Please don’t point that out.

 

[Rhotpursuit]

If you're putting a supercharger on it, I'd think computer mapping is out the window. You going to have to tune it anyway.

 

[oldeerslayer]

The 4.3 has many variations.
Read this: V6 Chevy 90 degree engines

About half way down the page is a section titled
Rebuilding the New Chevy 262
which goes into all the idiosyncrasies.