A lot of people run 3.50 gears in street rods. Just figure out your rpm at speed with the type of transmission you are running, the diameter of the rear tires, and the cam manufacturer's recommended rpm operating range. CompCams recommends it's Magnum 280's operating range from 2000-6000 rpm, so I planned accordingly. In town, I never use overdrive. But with the low rear gears, it works great in drive. The engine does not like running under 1500 rpm, but the tranny usually shifts down to compensate. If I had the extra money when I was building the engine, I probably would have gone with a Magnum 280 hydraulic roller and a rev kit. But I figured that was simply overkill and I could do without it.