How to??

I have a stock 2V distributor with vacuum plugged and it goes to 45+ at 3000.

This is a single point? I don't know if the FBO limiter works with dual, I'm sure you can get ahold of them

Crackedback, I think, posted a set of measurements for recurve slots, but again, I think they are for single point. I would guess that a "starting point" could be based on a percentage decrease in the slot length of "what you have." You'd have to carefully measure the advance of what you have now.

Basically, you just weld or braze the slots shorter and file them out. Be careful not to damage the SIDES of the slot or the pegs may "catch" There was a Hot Rod or similar article

Here we go

Mopar Electronic Ignition System - Mopar Muscle Magazine

Here's one from Jalopy Journal

Fixing a bad curve....

Bear in mind that as you read about this, "traditional" distributor specs were given in DISTRIBUTOR degrees, which gives you TWICE as much advance at the crank

I think I got this from Crackedback. Again, these are distributor degrees

Dimensions for Mopar distributor slots, in DISTRIBUTOR degrees

Modifying advance slots
degrees / slot size
6.............. .340
7................355
8................375
9................390
10...............405
11.5 ...........420
12...............435
13...............445
14...............460
15...............475
16...............490
17...............505
18...............520