I believe the 235 was available in the larger 'bolts going back to the early '40s. The one in your truck looks to be a later engine, not the 235 "babbit pounder" that was original, but a full pressure 235, could even be a 261.

If memory serves correctly, the passenger car 235's were blue, the truck engines were gray.

Someone will surely come along and correct any misinformation I've given here.