Trans vs rear end

[apachedaddy]

I'll be home soon and wanted to know you thoughts. Do a 700r install or gears for the rear for better highway speed. Not looking to hot rod just want to cruse at 65 without being tached out. 700r would cost alot more to do than the rear end but has better top end without the gear change. But i could do the 5 lug conversion and get posi with lower gears(3:08s maybe??) for alot cheaper.Its on my 66 SWB. So spend the dollors on the 700r or just do the rear end and use the rest else where???? It has 3:73/6 lug right now and a 350/350. Thanks for your thoughts..