You have to be adding a lot of Lead Subsitute additive to prevent from damaging the valve guides. Unless your running Aviation fuel your low on octane.
When I got this from my dad in 2000, I was forced to re-jet the carb to keep it from pinging. It's been in the family since 1970. Remember in 1968, we had leaded fuel where the low grade fuel was 98 octane ($0.19/gal), premium 102-103 ($0.26/gal).
I replaced the original heads on mine to the Edlebrock 428 Al heads, So I could burn this Unleaded fuel. Along with roller rockers, cam, intake and carb, Ignition system, just to name a few items.
Mine has the C6 transmission which I have rebuilt and installed a shift kit in it. Even with the C6 I can lite the tires up in all gears.....
I have done all of my own work. The only work that I have paid for was machine work on the block and crank. I even did my own balance work on the rods. The only thing I have not gone through yet is the Ford 9" rear end. I have a spare 3rd member which I'm going to set up with a locker.
Mine only average 8-9 mpg,
If I keep my foot out of it. Which is very hard to do. Which only gives me ~140 miles per tank. The reason I added a rear 26gal aux tank.