i just bought a 98 s10 blazer would a 4.3 liter vortec out of a 94 be compatible? what are some of the problems i would run into if it is?

 

Swap heads, intake manifold, and block sensors and it should work. Check into the timing cover too.
this article has more info for you to sort out.
http://www.babcox.com/editorial/ar/ar39840.htm

I swapped a '85 into a '93. My problem was th oil pan and one accessory bolt hold int he pasengers head.

An easier swap fro you would be a '96 or newer block, however sometimes you have to deal with what you have on hand. Post up and let us know if you have any more questions or at least gives us some progress updates.

By the way, welcome to the site.