Looking for advice on how to bolt some power into my 305 1980 caprice

Its not the stock motor it was swapped in from a Camaro (not that that means much in a 1980's 305) i put a Holly Street Warrior on it since the old one wasn't working properly it runs and drives great but its a total dog with the boat anchor that is a bone stock 80's 305 i want to put in a decent cam nothing crazy but something with more life than the stock one. and a Edelbrock performer intake but im not sure which one would be best.

at this point i should add i know a 350 would make more sense but i'm on a budget and the 305 is in great shape

also some recommendations for headers that would fit without being bashed into oblivion it does not have ac but it does have power steering

any help is good help

this is the car

 

you can find a 350 and get more power out of it stock for cheaper than trying to build a 305