What kind of horsepower to expect 383 build

340dartley said
Yes. I did. The other concern I had with advancing the cam was the already high compression ratio. Advancing the cam would increase cylinder pressures at low rpm potentially eliminating any hope I have of running this on a pump gas mix

Don't worry, if it really is 11.5:1 compression, even with that cam, it still isn't going to run on pump gas.