I have a 93 z24 and it has over 100k miles on it and I want to make it quicker but i dont know if i should get a new engine or rebuild it. anybody know on average how long it would last if i rebuilt it??

as long as any engine, It just depends on how you treat and maintain it

ok well if i wanna put a new engine in what engines are compatible with a 93 z24?

The 3.1 you have is pretty tough, it can take a hell of a beating and keep going. Obvious swaps are a 3100 and a 3400, though some have gone as far as putting in a 3800/3800 Supercharged.

My old Z24 had around 160k on the odometer when I sold it 2 years ago, and it still a daily driver for a guy I know.

are those engines fast and can be modded good?

1 - English is your friend.

2 - Higher numbers than a 3.1 if that's what you're asking. As far as modding, anything can be beefed up quite nicely if you know what you're doing.

ok, u know anywhere to get em cheap?

cheap and speed usually don't go hand and hand