how would you guys built it?

If your not going for a race/street car, I'd go with 3:55 gears simply because the car will be easier on the gas mileage, easier to live with on the highway and if you don't have a built up 360, it will be easier on the engine as well. The 904 will benefit from a shift kit and stall but probably not much if your going for a relatively stock build.