For the search archives, for those who may like myself have been running Kadron 40s and found that the vacuum signal was inadequate to get the desired benefit of an SVDA distributor running with the set up, I may have discovered the trick.
I purchased my Kadrons stock (without AJs or Kaddieshack's vacuum mod), as I've learned what the ported vacuum mod entails and it was something that I was mechancially able to tackle. However, what I didn't understand is that in doing the ported vacuum mod while you will get ported vacuum, the signal is pretty weak, e.g., 4 to 6 inHg, and not enough to budge a vacuum canister of an SVDA dist.
You need to do something more than just remove the brass plug and install a nipple. You need to drill out the vacuum opening in the carb body behind the plug. I found that the vacuum opening was barely the size of a small paper clip and very restrictive. I drilled out the opening to 3/32in. and was able to increase my vacuum signal to 10inHg. I also cleared up molding junk in the throttle body vacuum opening to make it less restictive as well. The exercise is to make the all of the vacuum openings communiating within the carb and thottle body as open/unrestrictive as possible.
After doing this (and connecting the modified carb with my SVDA and test driving) I believe that my timing associated flat spot on acceleration is gone (though I still get a hickup now and then through a carb,which I believe is an accelerator pump adjustment issue as the timing is good and carbs are synched).
Next weekend I am going to do the same thing to the passenger side Kadron so I can tee the vacuum signals from both carbs to help stablized and make less peaky the vacuum signal currently produced from the single carb.
But this (just opening up the ported vacuum internals within one Kadron) was a big improvement.
