A 4.10 should work just fine with a direct drive 4th. gear- - - -the 235/261 engines are not the fragile little wallflowers people seem to think they are. They were intended to run all day at or near their max RPM/horsepower rating in trucks, and some of them had rear axle ratios in the 5's or lower. Make sure the rod bearings are in good shape, run the engine around 3K RPM, keep it well-tuned, and change the oil and filter regularly. You shouldn't have any trouble keeping up with traffic.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!