Have your heads milled to increase compression a bit.It can only help.

I have a 75 Newport with a stock rebuilt 440.Runs fine.Maybe I will get off my butt and put my C body 1 3/4 Hooker headers on there as well as the Performer intake and 750 vacuum secondary on the shelf.Probably have a small cam I can throw in there as well.With the 11" converter(on the shelf) and 3.21 limited slip in the 9.25 I can be blues brothers fast.