my s10 currently has a 2.5L l4 engine with auto tranny. i am wanting to swap a 2.8L v6 auto tranny in to it.
i need to know the following.
1. will it fit.
2. will my 2.5 tranny work on the 2.8
3. will i need to modify the exhaust.
4. what extra work is needed.
thank you and please get back to me via this or at dblake8806@yahoo.com  

Since there were a lot of S-10s with the 2.8, it should be fairly straightforward. You'll probably need different engine mounts, and if you get a 2.8, make sure it's for a longitudinal application. There were a lot of 2.8s in front-drive applications, but I don't know if the casting or bellhousing is the same as rear-drive models. And it's always best if you can find an engine & trans together. Usually makes the swap process smoother. My suggestion is to find a totaled S-10 with the 2.8 with engine & drivetrain intact and in good shape. When you have a complete (or near complete) donor vehicle, it may end up saving you a lot of headaches.  

If you are going the trouble to swap the engine why dont you use a 4.3? Aftermarket parts are eaier to get and you could get a MFI turbo version out of a wrecked typhoon or tsunami if your looking to go fast without a V8 swap. The 4.3 engines were avalible in your body style from 1988-1993.  

Good point. The 4.3 will give you a lot more power, and should swap in pretty easily.  

The power gains aren't even worth the swap. Go with the 4.3.  

Well, the other option is the GM 3.4 crate motor. It has all the same external dimensions as the 2.8, and all the engine accessories & belt drive from the 2.8 will bolt right on. but it really only makes sense if  you already have a 2.8 and are doing an engine rebuild or exchange. If you're doing a full-on swap, I'd probably go straight to the 4.3, too.