Try to leave the needles alone, if the motor has good draw on the carbs you may well not need to screw with them. I don't. The pilots are fine, don't mess with them. Start at 10 higher main and go from there, may not even handle that if you are running stock exhaust. The condition of your engine seal as in valves and rings determine a whole lot of what you have to do, way too many people just assume a 35+ year old engine is still sealing well and big mistake #1. Look at your compression; you are already down a bit if the numbers are right. Should be able to get 150+ with a good sealed engine.
Like said above , a whole host of variables there yet everybody wants to know EXACTLY what numbers to run. Like it could ever happen..............one guys' hot rod is the next guy's dog.............
Header CAN make a big difference but not necessarily. There are a whole lot of 'headers' out there but the number of them that really work well, you can count 'em on one hand. I personally think pods with no header are an utter waste of time, you always mod exhaust first, it leads to an intake that then can flow more if you mod it THEN. If intake can't then modding it to do so wasted time. The old treat the entire thing as a unified system thing, you don't think of intake or exhaust as separate, one affects the other.