So I picked up a 1990 Nissan 300 zx non turbo for 350$ and the tranny went out... how hard would it be to swap to a manual? Will it bolt right to the motor thats currently in it?

No. And lot.

the $350 you spent is just the beginning- better build your bank account up into the thousands- I hope you love the junk because your love will be tested- I know- I drive old junk and am fixing it up as I go along- whew!

What do you mean when you say it went out? What are the indications/symptoms? How many miles on the odometer? Sometimes when the seals inside the transmission are old, they become stiff and cause slipping. Adding a quart or two of Barr's transmission restore (remove some fluid first if you add two QTS). The fluid adds flexibility back to the seals. This is just a short term solution, but it can get you back on the road.

The odo says 191xxx drop it into drive I can feel it catch a bit when I hit the gas it revs up and doesn't want to go... drop it into drive one it feels like it starts in second gear but slips but blows ignition fuze... I think its a fuzed wire beings they ran the wire harness along the exauhst pipe... I really just wanna swap to a manual... I dropped two quarts of that's barrs two part stuff in there all ready and didn't do anything... I know someone with a 88 twin turbo manual and I just wanted to know if Icould swap straight over...

Swapping to a manual transmisson is al most like trying to change the engine u got work your way around everthing u have to unbolt all the junk surounding the transmisson