'51 Hudson Hornet Distributor Swap - Distributor Cap/Rotor Question

HoustonHudsonHornet

I'm swapping in electronic ignition and plan to run it with a MSD 6al that I have collecting dust.

I've read several posts where people have used a chrysler electronic ignition distributor to swap into a 308.  So, I already have the distributor from a 1973 Dodge Dart 6cyl.  I've also fully disassembled the 308's distributor.

What I can't find in those posts is info about which cap/rotor to use.  I have my suspicions and it will probably be obvious when I get all my parts delivered, but I wanted to pose the question to y'all.  

Which cap/rotor do I use?  I suspect I'll have to use the 308 set because the rotors attach differently.  Since I'm using the 308 shaft, I'll need the 308 rotor, which means the 308 cap as well.

Does that sound right?  Any other specifics those in the know can pass on?

Thanks,
Ryan

hudsonguy

You'd use the Mopar cap. Basically everything is Mopar, except for the shaft that engages the oil pump/camshaft and the vacuum advance weights, which should be from the Hudson distributor. It does require a bit of machining on the body of the distributor where it enters the Hudson engine, as the Mopar unit is slightly bigger diameter.

HoustonHudsonHornet

Thank you for that, hudsonguy!  I did read about the machining that will need done...going to hopefully be able to do that by hand.

I should have all my parts on hand this weekend and I'll get to actually get to put it together and see it for my self.

Just for posterity...or just to get it in a more recent post...here are the part numbers I've gathered based on research from older posts (please feel free to correct me or add info):

Electronic Ignition Upgrade
Lookup Car:  1973 Dodge Dart 3.7L 225cid L6
Distributor:  Cardone 30-3690 from RockAuto - $55
Cap/Rotor:  Wells CR2201 from RockAuto - $5
Wires:  Accell 5041K off Amazon - $55
Ignition Control:  MSD 6AL from a shelf in my garage (hope it still works)

I also bought the Hudson Cap/Rotor - whether needed or not.  Here are the part numbers I found:
Hudson Rotor:  AL152 from RockAuto - $4
Hudson Cap:  AL138 from RockAuto - $6.50

HoustonHudsonHornet

Just thought I'd update since I have successfully completed this upgrade!

I have worked with distributors before and swapped gears before, but never taken one apart to this extent.  Here are the steps I took in case anyone needs it in the future

The parts are listed in the previous comment.

1. Remove original distributor.
2. Remove original cap and rotor from distributor.
3. Remove hold down and timing plate.
4. Remove the Vacuum Advance.
5. Remove the points and condenser.
6. Remove the pin holding the shaft retainer in place.  The original was stamped into place, so I had to grind the head off one side and then punch it out.
7. Remove the shaft with advance weights
8. Now for the new part to me:  looking down the shaft at the weights, there is a little clip that holds the original points actuator part (proper name?) and upper shaft to the main shaft (with the weights). Remove this clip and pull that part off the original shaft.
9. Set the shaft with weights, the distributor mount/timing adjuster, and the shaft retainer/shims aside for reuse.  All other parts can be boxed out of the way.
10. On to the NEW distributor:  Remove the cap and rotor (if included)
11. Remove the Vacuum Advance
12. Remove the electronic ignition pickup
13. Same as Step 7...There is a little clip holding the pickup actuator to the shaft.  Remove that clip and the upper part of the shaft.
14. Remove the roll pin and gear from the shaft.
15. Remove the shaft from the NEW distributor body.
16. You should now have a bare distributor body...The mounting will need shaved down to fit in the Hudson block.  I accomplished this with some 80grit sandpaper and a metal file VERY slowly and checking fitment often.  There are probably more precise methods, but this seems to have worked.  I finish sanded with 600grit, just to smooth it out.
17. Install the upper part of the NEW distributor onto the original distributor shaft.
18. Install the modified shaft into the NEW distributor body.  I used the roll pin from the NEW distributors gear to hold the original retainer in place. I'm not sure how much in and out play should be in the shaft when installed.  I used the shims to get it pretty close to no play, but left what I felt like was enough for some expansion.  This play is ONLY in and out.  The shaft should fit very tight into the distributor body's bushing.
19. Install the electronic ignition pickup
20. Install the Vacuum Advance (I used the new vacuum advance).
21. Install the cap and rotor.
22. Install hold down and timing plate
23. Install in engine!!!

At this point, I made new plug wires, installed new plugs, set the rough initial timing, and temporarily wired up the MSD ignition box.  She fired right up...until the carb ran out of gas (another post for another day...Fuel Pump upgrade!).  That's the first time she's ran in I'd guess 15 years or more!  SO EXCITED!

Glowplug

Ryan- Great writeup / would like to offer you opportunity to join our South Texas HET Chapter.   Contact me through the email associated with my account.  BTW we had our last meeting in Cypress.  I and Chapter president will be back in Cypress on 24 April.  Maybe we can meet then?