The short answer is no. You will need some sort of mill/milling attachment. You can't remove webs and such with a lathe unless you can turn the piece, and there is nothing between the webs you want to save.

If I had to limit myself to one machine for the conversions you want to do, it would be a Taig Mill with a sherline rotary table.

If you look at an engine, there are only three things on it that are turned on a lathe. The piston, the cylinder, and the crank (with special jigs). So, if those are the only things you are going to modify, then a lathe will work. Anything else needs a mill

Don