A later model Best 30.
That is actually for the Cat 30 for use after discontinuation of the Stromburg that was used on the last Best 30's and the very first Cat 30's.
I have a Early PS-30 that would look better with the right carb if its for sale.
My thirty P.S. 90 has the caterpillar logo instead of the ensign logo on the float bowl. Is that a later float bowl or an earlier original that has survived?
Yellow, your float bowl is an earlier one that has survived.