Is a Holley 750 DP too much carb?

What I am after is what the heads are. Iron or aluminum. The amount of advance will depend on the metal as well as the chamber (size) in the head.

If it was an aluminum head, I would have told you 32-34 max total advance.

And not understanding is OK. You'll learn. Keep reading. You'll be fine.

If you want To spend the Money on an overdrive, the mileage gain is will be noticeable but not huge.

There is room for improvement but do realize the your .030 - 360 (365 now or 6 ltr!) is on the biggish side, well cammed and has a high gear ratio. So it will only get so good.

The key here is to keep at it.

What size tires are on the rear of the car?