I want to replace 5 hp gas engine.. on a log splitter with electric What size motor should I be looking for?

I have done that switch. A 5 hp electric would be great, but it will run on a 2 hp. I used a v-belt drive so power can be adjusted by using different size pullys for gear reduction. Be sure to get a single phase motor for house current compatibility. A smaller motor with gear reduction will slow down the splitter somewhat. Actually, hp is figured differently on electric motors. A 5 hp gas engine is equal to a 3-4 hp electric. You will need to run a 240 circuit for an outlet to plug in the splitter. It is nice not dealing with gas, oil and smoke. No more hard starting and you can run it indoors if you wish. Northern Tool is a source for motors, unless you can find one elsewhere (ebay).