Cruising the pits at the Bonneville Salt Flats I saw a tow vehicle with "There's no substitute for cubic money," in nice script painted on the side.
You could keep the 216 and just turn it faster. With some period speed equipment you can up the power a bit and look cool at the same time. Maybe Hot Rod Lincoln could fix you up with a crank drilled for pressure to the rod bearings. Switch to an open drive line rear axle and a three speed overdirve transmission. I think they were available for Chevrolet cars from '55 on. I had a daily-driver '50 Stude for 10 years with 4.56 gears and an overdrive. It effectively had 5 usable speeds and got consistently 28 MPG on the road. It would make a comfortable 60MPH. A 4.11 run through a 30% overdrive would give you a 2.88 final drive ratio. That, with a five-speed trans should do nicely in an AD pickup. A 216 will have way more torque than a flathead 170 Studebaker and the later 3-speed trans was a big improvement. Might be cheaper than finding and rebuilding a 261 and you'd surely get better gas mileage than a 261 run through a straight 3-speed and a 4.11 rear.
