1937 Deluxe 8 axle ratios?

I have a 37 straight 8, the engine is very smooth and torquey but the stock rear end gearing has it running out of (comfortable) revs at about 45 to 50mph. I live in a flat area and the engine could easily turn a higher ratio which got me wondering, what ratios were available from factory? I'd like to track down a taller gear set and install.

Anyone?

The standard ratio is 4.37:1. You can measure it to check. I see it has an open drive shaft which makes it easy. Make a chalk reference mark on the diff and driveshaft then jack up one rear wheel and count how many turns of the drive shaft it takes to turn the rear wheel through two turns. Straight eights always sound busy. Maybe you need to put a tachometer on it to measure what revs it is doing at 50mph. At a rough guess it will be about 2500rpm. Remember that in those pre-freeway days cars were built to climb hills in top gear.

I have since found that 4.62 and 4.125 were also options. A temporary tachometer had occurred to me, might prove valuable, the engine noise may just sound worse than it is. With my tyre size and 4.37 ratio, 50 mph should be 2509 rpm. I'd like to do some longer trips in the car, 60mph would be nice but I'd need more like 3.5:1 to make that comfortable.