68 340/68 valiant ?

I don't know, those 28 inch tires and 3.55's aren't going in the 12's, unless those cars are no more than 3,000 lbs.

It love 4.10 gears but not sure you will if the exhaust is loud--which like all are, lol. I run my 26 inch tires and 3.91's @ 75 mph plus for 10-15 miles. I run two high flow mufflers on each pipe to cut the noise down. Still its rocking. What a breeze keeping up with traffic is8)

Its a good combo and 3.55's are super gears for freeway driving, just don't expect 12.90's, IMO