The challenge is to get the same gear ratio. A max cog of 26t, which most RDs should be able to handle, with a 30t small front ring equals 31 gear inches. To get that with a 38t ring means going to a cassette/freewheel with a 34t max cog, which means a long cage RD with lots of wrap capabilities and perhaps new shifters. A compact double with 50/34t rings with a 26t max cog gives a low of 35 gear inches, but to get that with a 38t ring, you’d need a 30t max cog on the rear, beyond the capacity of many “classic” RDs.

Here’s a pic of the backside of those rings attached to a 110bcd arm:
https://cimg7.ibsrv.net/gimg/bikefor...699eb3a55.jpeg

Thanks for all the info. I like the Velo Orange and White Industry cranksets. I think I'm going to go with a modern 11 or 12 speed set up (my Ultegra 11 speed fits fine). I would like a nice crank to set it all off. The frame should be re-painted by the end of the week and I intend to build it up from there.

How about a 144bcd classic crankset, and much larger testicles?