I'm a new member and I recently purchased a 1999 2wd Blazer with 137k on the motor, which I just recently, notice the oil pressure starting to get really low and started to notice a slight lower end knock not very loud though. I have a feeling she isn't going to last long so I decided to switch to a heavier weight oil 10w40 with 1qrt. of Lucus oil treatment and that seems to help a lot. I then picked up a used 4.3l from a s10 , I believe is a 1995 block which has the old style intake manifold. My question is can I use the short block only and transfer the manifold from my 99?. I have not found any information saying that 4.3s blocks and heads were any different form 94-04. I plan on rebuilding the 95block and heads and have it ready to use once my current 99 block craps out. Any Information would greatly appreciated and Thanks.

 

Lots of differences. Read this.
Rebuilding the New Chevy 262 - Engine Builder Magazine