FWIW: Car Craft has a tech article with a carb’ed 305 wagon (like mine ~was~) They put a 100-150shot of N2O on it and got what they wanted from a lowly 305.
But, since ur talkin about a just a tune up…I’d get plugs (maybe one range colder than stock and bump the timing a bit, stock is waaay conservitive) …just because, and wires…they could be fine (check resistance in the wires) or get some aftermarkets…AC Delco are good stuff, got em on my wagon and my GP.
Flush the coolant, if u dont mind changing it again in the fall…I’d wait till may or june and use straight distilled water with Water Wetter. Pop in a 180 degree T-stat if thats in question. Use Mobile 1 10W30 or SAE30 syn.
Oh, and get the K&N it makes the car sound louder when u get on it if not anything else 
Good luck!