What size do I go with?

I just picked up a 1998 Chev Cheyenne with 4.3l v6, body in good shape but needs new engine just wondering what to put in there and also what vehicles could I get the engine from?

The most common for this series (1988-1998) is the 5.7L/350ci...best being a Vortec version from 1996 up. Much better HP and economy compared to the previous TBI version and boatloads of performance options. Or you can go big-block 7.4L/454ci with big performance right out of the crate. Don't bother with the little 5.0L/305ci. You've got lots of good options..enjoy!