Gear Ratio Swaps?

[blkcorvair]

My 69 is finally done and I notice this thing is revving on the highway. To the point where I feel uncomfortable at 65 mph. I generally toot along at 55-60 but everyone is passing me up.

I have the 250 3OTT with a posi rear. Im gonna chack my ratio tonight but I suspect it to be 4:11.

I was looking at swaping in a lower ratio like 3:42 or even 3:08. Its strictly for show and I wont be trailering or hauling anything, but would like to be able to go down the highway and maybe even pick up some mpgs.

I notice the aftermarket gears reference two different carriers. Gears to fit a 3:73 and up and those to fit a 3:42 and down. Do I need a different carrier to swap in some 3:42 or 3:08's? Any other pros/ cons?

Thanks!