If the PO reworked the carb so it would get the mpg of a 250 it would be "Cold Natured". PO has it running real lean, if it's not over heating when you push it for a while, it's OK. Don't over advance the timing. Hotrod is right Qjets are the best carb for no hassle. Check your choke should be 1/4 to 3/8 open when cold. Floor once before starting the motor to get it closed, then check. The oil gauge in my 68 went out at about 120k. You should be able to see an 1/8 inch oil coming out of the fire wall up and behind the wiper washer lines. If is like my 327 then it will go to the back of the block to the right of the dizzy. Learn to read the vac gauge lot's of things it can tell you as to how the motor is running. Wish I had one in my truck.
Larry

I don't own a vehicle that isn't old enough to drink.