I want to know if I can change a 3 cyl manual car to a 4 cyl automatic w/o any changes in engine compartment?

Question

1995 GEO Metro 3 cyl 1.0 lit with manual trans

Answer 1

Sell the 3 cylinder version, buy a car with a 4-cylinder that came that way from the factory. It's a whole lot less work and hassle, and it'll run better, last longer, and have a better resale value. It'll probably be cheaper, too, because you won't have to buy or make custom parts that are different between the two. And unless you find someone who's done this before, you'll probably find that you need odd little things you never think of to make it work, like left-handed motor mounts, adapters, a longer or shorter driveshaft, shift linkage mountings, and so forth.

Unless you're really looking for a project, save yourself the headaches - just sell one, and buy the other.