1937-1938 the T14 (37 only), T-16, T-16H, F-16 and F-16H use the OLDs 230 CID. Midyear 38 a 1 1/4-ton walk-in panel delivery van use the 230 OLDs. GMC 228 and 248 replaced the Pontiac and OLDs engines in 1939.
jimgmc, Many thanks for those tidbits of info! After doing a little more web searching I see that the T-16 and F-16 models were the larger trucks as I came across some copies of dealer handouts indicating they were 1-1/2 and 2 Ton sized trucks. Saw a Dealer handout for a 1938 GMC "Special Delivery" truck that said it used the 230 engine also.
I think I am going to do more research to try and confirm what trucks this pump fits before I do anything else as I want to make sure it is accurately identified.
