The Olds 260 head is the worst flowing factory head?

[olds307 and 403]

You would want about as deep of gearing that is available for 7.5" rear💡. The minimum I would go is 4.11 with a stock height 25" tall tire. The .50 overdrive means like 1650 at 60 mph with a 25.2" tall tire and 4.11 gears.

 

[84dragcutlass]

Yeah i was thinking a minimum of 3.73 gears, the 260 basically just has torque (not a lot) but the gears would help it with the overdrive