To do the conversion isn't that bad of a job to do. And like Jay said, get a A9L computer and the harness pigtails is all the money you will really need to spend. There is also companies that make a harness to eliminate all the fabbing up a harness.
Yeah that is usually the best route to go. That's what I did with my 331. If you have a certain goal with your engine sometimes these generic rotator kits don't cut it.
Well just be carefull because sometimes with Eagle you get hit or miss with pistons they include with their rotators. I have ordered 2 rotators from them both identical kits and 2 totally different piston sets came with the 2 kits. Sometimes you might end up with a hallow dome forged piston...
The engine I am currently putting together is a 11 to 1 solid roller cam with a low .600s lift cam, AFR 205 heads with a Jesel set up, and a Victor JR intake. A combination like this is good for a low 10 second pass in a 3,100lb or less chassis