360 in a 75 Roadrunner

ir3333 said
3.21 / 3.23 are great gears and i'd leave your 3.21's alone unless you go to a 27 or 28" tire.
.. a call to one of the converter manufacturers will get you what you want.

I can still remember my 70RR........3.54 and G60X15 results in 3000 @ 70mph. JUST RIGHT!!!

(Actually Wallace says 66.6 but that was before Al invented the internet!!)