JMO413 got the build sheets for my 89 LWB and 90 SWB and they say this, I don’t think he edited them:
NF2 18.5 g fuel tank on the 90 SWB
NF5 23 g fuel tank on the 89 LWB
both correct
These were gas tank codes (not all MJ) from the 1989 (I think) code list Pete had found and posted, I put it all into an Excel sheet:
NFA
20 GAL TANK FUEL
NFB
22 GAL TANK FUEL
NFE
30 GAL TANK FUEL
NFF
35 GAL TANK FUEL
NFS
15 GAL TANK FUEL
NFU
34 GAL TANK FUEL
NF2
18.5 GAL TANK FUEL
NF5
23 GAL TANK FUEL
The 16 gallon tank was one offered in 89, from the 89 sales book: