M37 Spark Plug wire Replacement

[rob love]

That is getting a little harder to source, as the manufacturers seem to have dropped most of them. This is based on you having the original shielded plugs, or has yours been converted over to civilian plugs and wires?

The military used to use Autolite AR5S and AR7S for cold and hot service. The hotter plug was also better if your worn engine was starting to foul.
Those later became autolite 2243 and 2245. Champion had XMJ14 and XMJ17 as equivalents. Those were recently changed to Champian 588 and 517 respectively.

Most are now out of production, and prices are starting an upwards creep to $25 a plug and more. So it behooves one to clean and gap the plugs, and if you have access to a tester, check their spark under load.

Watch out for some of the plugs unscrupulous ebay sellers try to flog as being for the M-series vehicles, such as the AR8S. They are for the generators, and have a different porcelain interface.

There are a few other part numbers out there, but the above will be the basics.