I own a 76 33 aswell.
Its an awesome boat, you will love it.
shes fast, points well, doesnt need alot of wind to move but hates wake on the quarter stern.
I have all the original build sheets,engine manuals,brochures,wiring diagrams,places to find original/aftermarket parts etc....
I also have a large sail inventory so if you need any measurements or choices on what to use and when lmk.
Dont fear the atomic 4.Its a great engine and with a little knowhow they are super reliable, smooth and very easy to work on.
Prop choice is vital as she has a reduction gear tranny.
Things to keep your eyes open for are the coring on the deck, the
seating of the bulkheads,cockpit floor core, sail locker covers, coach roof near the upper
winch plates, toe rail to deck seal, engine and sailing instruments, the windows for water leaks and all the other things associated with a 33 year old boat.
My boat originally came out of salt water and if this is the case on the boat your looking at I would go over all the thru hull fittings and fresh water system for the engine very carefully.
Chances are the hull will be fine as they were built like tanks.
If you have any questions at all just send me a pm.
Congrats, you made a good choice.
Chris.