Dizzy recurve for 440 MH input

What I would do before anything is just do some simple lookin around. Distributor advance might be seized up. You can pop the cap and twist the rotor and see. It should twist (I forget which way on a big block) and then spring back into position when released. Make sure it springs back all the way. It might just need some simple repairs.

I mean after all, it's never gonna be a barn burner, but you can make sure everything works as intended. That would be a start, IMO.