I think that's what I did with mine, used 2 of the factory lighter springs. That will increase the advance rate a little, just not as much as the super light spring. I'll defer to
@Slantsix64 as I just don't have his experience.
Regardless, you should probably put new plugs in, I used the extended tip NGKs that Slant Six Dan recommended. They are the smaller plugs with 5/8" hex but you still remove the washers. He says they are the best for a slanty.
www.forabodiesonly.com/mopar/threads/spark-plugs-for-slant-six.130467/#post-1972971916
P.S. a GOOD condenser reduces point pitting. I still have points in mine too and checked the dwell before driving to Carlisle last July (320 miles each way on one tank) and it was in spec.
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I actually have the FBO limiter plate and lighter springs in my stash but I wanted to experience the "pure" slant six excitement before I started changing things. My parents had 61, 63, 67 and 73 slants but this is my first. I've been collecting parts and have split exhaust manifolds and a 2 barrel intake with carb to go on but first....swapping in a 4 speed that I'm in the middle of rebuilding. I tried "racing" my 64 Val with the 3 on the tree and it was not too good. Managed a best of 18.51 but I'm curious what it'll do with a trans I can actually shift quicker.
