Overdrive or don't worry about it? !

Good morning everyone!
Some of you might know I'm doing a big build on my 1968 Barracuda. .....currently having a 318/392 stroker built over at IMM Engines. .....

So, Freeway driving. .....
I'm seriously considering an overdrive for cruising the highway.
Or, do I really need one?

Only really want to freeway drive a few times a year.....maybe 100 - 200 mile trip or two (each way) a year.....the rest of the time would just be romping around town.

When I'm on the freeway I don't want to limit myself to 55-60mph....I'd get run over here in Southern California! It would be more like 70-75mph.

So, do I really need to worry about an overdrive?
Would driving at 3000 - 3500 RPM a few times a year really be all that hard on my engine?

I'm probably way over thinking this but I value all your opinions.

Gratuitous photo of said 'Cuda

image000001(8).jpg

Jeff