4.3 Blazer motor

I have a 1995 Blazer with a 4.3 Vortec motor that has a slight crack in the cast block and I was wondering if a 4.3 block from a older Blazer would be the same?

as long as you get one with the balance shaft you will be ok (the CORRECT balance shaft - there were 2 versions)

Know a guy with a big semi. Cracked block in the big diesel, antifreeze leaking. Ground it down and covered it with JB Weld, fixed it for a couple years of hard use. Amazing stuff, I use it quite a bit. If the engine is fine otherwise, worth a try if you can get to the crack and get it clean and dry.