80 mph highway speed in a street rod!!! That doesn't give the average interstate driver much time to look at the street rod caravans as they go by. LOL! Dan Spec, you should figure what rpm you want to run the 302 at and what rear gear ratio and tire size you now have and make your trans selection from those. I would think you will need an overdrive, but you may find that you are geared for a non overdrive trans. As Tech mentioned, camshaft will influence this selection too. A 9" Ford rear sure comes in handy for these situations.