Hi nathan80,
seems your mouse motor has been open for some while. You'll have some dirt in it most likely. Of course it depends on exactly what you want to do with it, but if this is your first build and you don't want to change too much performance wise I would do the following.
1. Buy a good Chevy-book (Vizard, Haynes, whatever)
2. Take the engine apart as the author of the book tells you, go step by step.
3. clean all the parts and measure them for out-of-round and whatever is needed.
4. only replace broken or damaged parts.
5. Put it back together in the way the book says.
6. Use good tools.
The reason I'm saying this: Many people buy a junk-yard engine, put a new cam and new heads on it, buy a "big" carb and then go shopping with their "new" engine. This thing won't survive. You want to know the exact specs of the engine and the condition of the parts you're reusing before you determine what is possible with the engine at all.
If you do the atop mentioned you'll get a nicely running motor, which is the best starting point. THEN you can go out and get a different induction system, new heads, a cam. Almost always, the first build doesn't fulfil the expectations of the builder. Don't be put off, just go on, like most things, you need TIME to improve your skills...
JMO, Max