Has Anyone ever changed from carbs to elctronic fuel control on their 500 hps, having an issue on one, just about tired of it.
what are some good options?

I use the Holley MPI kit. It has a single plane manifold with a 1000CFM throttle body. I upgraded the injectors to 42lb. It has a laptop programable ECU that you adjust on the fly. Are you a do it your self person or will you have to pay to have it done? It is very time consuming. It will probably not give you a big HP gain, however it will start and perform better. The kits are not cheap about $3000. You may be able to find a factory setup from a 500MPI.

Would probably be alot cheaper/easier to send your carbs out to Nickerson, and have them go thru them. It will be better than new.

Stick with carbs.

EFI is nice, but for the money I would put it into some more go fast equipment.