I have a 65' Impala with a stock 283 with headers and a rebuilt powerglide. I want to get more HP out of my 283. Where do I start?

 

Yeah it used to have a 2 bbl carb on it, but I put a Holly 4 bbl 650 cfm I think with an electric choke.

 

i know the old heads are getting hard to find now a days ,but if you could find some old power pack head's off a 327 325 hp engine with a mild hydraulic cam would wake it up .650 carb and a good dual plane intake .you got the carb i dopnt know what intake .