You bought it from the previous owner.. not a wrecking yard.. if I understand correctly. If it was a wrecking yard, I would go through the trouble of draining and flushing the tank... but im fussy.
Sounds like you ran into an excellent project. I have had a 72/73/76/80/81 Celica... (not listing the Corollas) and the only thing I didn't like about the 76 was that the car was solid, but the gas pedal was super light. I had to keep it pegged to the boards... it just wouldn't resist my foot.
Rebuilt that motor and if I remember right it didn't have the dual webbers, but I did have a Prelude with duals (thats stock on certain years). The only issue with them was the rubber intake pipe cracking (spider cracks). I duct taped mine just for fun and it ran great. Very nice car, those 76's. Handle really well and if done nice are pleasing to the eye.