Have you tried a known good condenser? As mentioned in the other thread the new ones, are not specifically too good.

Installed the heavy gage battery cables today (made by NAPA).   The engine turned right over (with the original starter) in it.  So now I have the brand new starter that I will keep,  just in case.  Cable size was the fix.  When I started to dress up the engine compartment, I started replacing battery cables.  They were lighter gage......no good.   Thanks for all the help and ideas  

I’ve flipped the starter ring gears on standard trans flywheels without issue but if a new ring gear is available and time is not an issue, then by all means purchase a new ring gear.  If flipping the ring gear on a V8 flywheel, then be sure to clock it 45° different than where it was originally so that the new side being used is contacting a fresh set of teeth.  You’ll find starter wear marks each 90° on a V8 ring gear and 60° on a six cylinder and you’ll want the reversed ring gear using a unused section of teeth.

Lorena, Texas (South of Waco)

I've heard of people flipping the gear but I decided not to try it and just bought a new one, they aren't expensive I think mine was $20. The ring gear also has a small bevel on the inside that goes against the flywheel.

This is slightly off topic, but when I first test ran my blown stroker motor the Bendix drive was hanging up on the ring gear. The flywheel I'm using was an 11" from a truck and when I had it resurfaced I noticed the teeth on one side of the ring gear were worn. I had heard that you can remove the ring gear and flip it over which is what I did after I got the flywheel back from the shop. I have since heard that the teeth on the ring gear are beveled on one side so that the teeth on the Bendix drive mesh smoothly. So, is flipping the ring gear to use the unworn side a myth or could my Bendix drive have a problem? The starter was a newly rebuilt unit by a local auto electric shop. 

  Ron Lane,  Meridian, ID

This is from a '56 Merc w/312 shop manual.

Ok, I thought you wrote they were replacing the starter because the bendix was extended.

Vintage MoToRs from the 50s or the Ford shop manual among other things they have very good tune up and troubleshooting procedures using a low ranging voltmeter and voltage drop testing the cables and connections, solenoid and so on.

The battery and cables, grounds, charging, generator, were considered integral to performing a tuneup, because a weak battery meant weak ignition and poor performance, especially under load.

The auto parts store is getting me the replacement.  I am beginning to believe the wire size of 00 is critical.  That's why my starter is "clicking"  I have 00 from output of relay to starter but from battery to input of relay is #4 wire.  When I went straight from battery to starter I used my jumpers #10.  The starter is on the engine, #10 jumpers wont cut it.  Starters on the bench will spin with #10 jumpers.
   VERY GOOD LESSON....ALL STARTER WIRES SHOULD BE #00..............INCLUDING THE GROUND CABLE.