Dave, if the cables are sized correctly, as Roy points out,
and 'all' the connections are clean, and you have a good 6v
battery that is up to par and not 10 years old and the starter
motor doesn't have bad bearings/bushings or worn brushes or
dirty commutator then that system is more than adequate to
start that 6 cylinder motor under almost any condition.

If it's not starting then the compression is way low, or it
needs an electrical tune up or it's not getting the proper fuel
metering or it's got the "Blue Funk" disease.

The reason the 6volt systems are given such a bum wrap is simply
because of poor maintenance. My '50, 216 is totally stock and
has been starting as it should summer/winter rain or shine
since 2005 when I brought her home. At that time I went over
the entire system, replacing, rebuilding and cleaning up
everything like it was when it was new and it performs like it
did when it was new.

Denny Graham
Sandwich, IL

Denny G
Sandwich, IL