Finally got around to measuring it.  Looks like Mallory was also careful to install the gear higher than FoMoCo spec (better too high than too low?). Variation in block machining must have been common knowledge in the late 50s.

BTW: As a side note, while many have stated that their non-vacuum distributor runs just fine, I haven’t read much about the gas mileage that gets sacrificed (?).

6 VOLTS/POS. GRD. NW INDIANA

The TSP distributor that I received does have an adjustable vacuum advance pot.  That’s a feature not normally available with the MSD distributors.  For dyno testing purposes I used the MSD HEI terminal spark plug wires that were being used with the MSD distributor.  The additional ¾” height of the cap posed no problem in installing the wires.

Lorena, Texas (South of Waco)

Based on their description, I think the CRT and TSP are the same distributor but sold by different vendors. Neither has an adjustable vacuum advance. Is that an issue? CRT's site said that 8mm Packard plug wires also are available. Has anyone purchased them with the distributor? If so, are they a direct fit?

Good catch as that was a typo.  I’ve gone back into that post and fixed that.  Only the inch number changed and not the decimal portion.  Thanks for the alert to that.

Lorena, Texas (South of Waco)

Good morning, Ted.

I'm confused by your numbers. There's approximately a 1-inch difference in gear placement between the CRT and the 57 manual specs. Is this a typo?

Thanks

Good information, thanks.....................

64F100 57FAIRLANE500

Paul sent to me one of the new TSP distributors designed specifically for the ’55-’57 Thunderbirds.  The packaging on the supplied box says TSP and not CRT.  This distributor is mechanical tach capable.  The quality of the parts looks good and some careful measurements of the gear placement on the shaft found it to be 4.983” collapsed and 4.998” extended.  The specification within the 1957 Ford service manual calls for the collapsed measurement or pushed up dimension to be 4.991-4.996” with end play being 0.022-0.030”.  My experience has shown that the distributor hole measurement should fall anywhere between the extended and collapsed distributor gear measurements.  I measured the distributor hole depth in the 312 dyno mule and it is 4.990”.  That makes the new TSP distributor correct in its gear measurement as the gear will not be in a bind when installed in the block.
 
As a FYI, the MSD distributors do have their distributor gears placed higher on the shafts (reduced collapsed measurement) than what’s called for in the Ford manuals but after having dealt with a number of blocks that are machined on the shallow side (not deep enough), I can understand the reasoning for having the gears higher rather than lower on the shafts.  Having the gears not running on the distributor pad in the block is not an issue for the MSD distributors.  No major issues with the gear being on the high side but any gears that are too low can have some severe wear issues in that area.
  
The distributor cap on the TSP distributor is ~3/4” higher than the MSD cap so switching the wires from the MSD cap to the CRT cap was not an issue.  Both caps in this case incorporated HEI terminals so no problems were encountered in switching the spark plug wires from one cap to the other.  With the ignition timing for the CRT distributor set exactly the same as the MSD distributor (39° total), the engine was run on the dyno and it made exactly the same horsepower as the MSD distributor so the electronics are doing their job.
 
I found no issues with this new distributor so I heartily recommend it to anyone with an early ‘Bird wanting to retain the factory mechanical tachometer.  Be forewarned that there are blocks out there with distributor cavities that are on the shallow side and appropriate changes must be made to accommodate those particular blocks.  That would involve either relocating the gear higher on the shaft for those shallow holes or a thin shim where the distributor and the block mate up to space the distributor up accordingly.
 
This particular distributor gets a clean bill of health and will be prepared for use in Paul’s engine.

Lorena, Texas (South of Waco)

It will be very interesting to learn what Ted finds once he gets one of these on his operating table.  If it has, as I suspect, a ball bearing instead of a sleeve bearing, there may be little or no axial float thus binding when clamped down. Often ball bearings have "some" interference fit. Curious to know if the strib has at least minimum .022" up & down shaft movement and what the distance of the gear installation is? It should be 4.991 to 4.996" bottom of gear to underside of the mounting flange with shaft pushed downward if I'm remembering correctly. If someone has one not installed,, a caliper would provide a good indication. The new strib may be made too precision and therefore not compatible with the manufacturing tolerances of the 50's. Just a thought...............


64F100 57FAIRLANE500

I think they did better 65 years ago then the Chinese do today..

Interesting. It hadn’t occurred to me, but I should likely measure the gear location on the 50s NOS Mallory Dual Point that I bought on eBay before installing it.  Quality control & machining precision is something that probably couldn’t have been taken for granted 65 yrs. ago.

6 VOLTS/POS. GRD. NW INDIANA