It seems that a constant thread on several message boards pertaining to M37's and such is what bulb to use in the various lights, especially when changing from the military 24 volt systems to a 12 volt system or when ordering replacement bulbs at a local parts house.
The bulb use and parts cross numbers that I used on my truck are:
|Application||12v Bulb Number||24v Bulb Number (what I had before converting)|
|Small bulb in front marker lights and taillights, dash lights||67 or a 97 (both work)||1251|
|Large bulb in taillights||1156||1683|
|Headlight||55-60 watt H4||70-75 watt H4|
|Turn signal indicator (in switch housing)||1445||313|
A nice chart showing 6, 12, and 24 volt bulbs including drawings showing the base types may be found at Jeff Smith's MVPC web page.
Pete, another M37 owner, sent me a MS Excel spreadsheet with bulb information from GE. The spreadsheet includes a lot of information such as bulb dimensions, power consumption, output, and life expectancy. It may be downloaded from here.
Ed sent me the following note on August 4, 2004:
"My local NAPA store said I could NOT buy ONLY three "1251" light bulbs
for my front instrument panel. I had to order a box of 10!!! NAPA's price is
about $3.50 a bulb. I was not going to pay $35 for light bulbs. After
searching the internet, low and behold, I found a source for these. I ordered a box
of 10 (yep!) from a pinball supply house in San Francisco AND the price was LESS than 2
bulbs from NAPA!!!! $6.50 for a box of ten. (there's a small shipping charge of a
couple of bucks.) The place is Bay Area Amusements. http://www.bayareaamusements.com/
Ordered online Sat afternoon and they arrived in Monday's mail, here in NJ.
Their shipping was quick. Their part number is LB-1251. Just another source that's inexpensive.