According to all of the Chevy literature, there was no 235 option for any conventional 3000 series AD trucks. 235's were standard in the 5000 and 6000 (and '50+ forward controls), but optional only in the 4000 series trucks.
I suppose if one knew the right people when ordering a truck, anything could have been possible. If John's '49 3800 really came with a 235 from the factory, I'd say it would have been very unusual and probably very rare.
