1943 K Runs Rough

My 1943 KS-5 runs rough. It's like a vibration it starts around 25-30 then smooths out some around 48. It's better when pulling up a hill. Starts great. Firing Order is good. 90-100 PSI compression in all cylinders. Haven't checked spark advance yet. Any ideas?

I'm guessing with the information provided. Is the speed range of the vibration the same whether the rear axle is in high or low range? Can you tell for sure whether it comes from the engine or drivetrain?

Dean

Do you get vibration when slowing the truck and in gear?
https://www.ericthecarguy.com/faq/deter ... vibrations

Could be unbalanced tires,

I had a K3 that whole thing would vibrate like crazy between 45 and 52, above or below was fine

The guy I got it from called it mach Buffett he said it happened all the time at those speeds,

Got tires balanced and front end tightened up, went away