There are well known published facts that the HP and compression ratios were speculative.

72 had 2 bbl. and either a 555 or 66 grind cam
71 had a 555 grind only
70 had a 254 grind

You could say 10 cc's difference between 70 (11) and 72 (7J2)could net you 65 HP.

Other than a few CFM difference in 2 bbl carbs, the heads and CC of them and the cam would be the difference.

My main point is the use of these heads and expectations. Unless you own or have access to a machine shop where these heads can be modified will the benefits be worthwhile.

Since is is unlikely to buy or find a servicable 2bbl. cam, I suggest careful exploitation of the "HP" numbers you seek. Too much of one and not the other is not good.

Not technically "back"...Thanks for the honorable mention Q. Just spent 16 hours installing Koni's and Hotchkis suspension, brakes and new bushings on the T/A and needed an outlet.