My C-4 is not really cutting it for highway use. I have been looking into going with a T56- 6 speed transmission and curious if anyone has done that conversion?
2.79 gears but Im still pushing 3100rpm at 75mph on the highway. The 6 speed transmission has a .80 5th gear and a .50 sixth gear which would be pretty nice for crusing the highway.
A T56 is huge x large with a built on bellhousing. Even a T5 will get your highway rpms down to 2000.
you should look into the T5 as mentioned above, cheaper to come by, way easier to install, and I have 3.25 gears, 27" tires and with my T5 I'm at 2200 at 75 . . . works great for me