My 360 build

318willrun said
i usually find where it wants to be at full advance. lets just use 36*. Then i set the initial, lets just say 21*. Your difference is 16*, so that is what you allow the mechanical advance to be. IF using the FBO plate, use the 16* slot and your set. Then you set what RPM you get your total advance with the springs.

dartfreak75 said
Thanks as always that's good info I looked up the plate your talking about. I may go ahead and order one.
FBO Mopar Distributor Limiter Plate

Since I am cheap, here is how I do it. I drill out (you have to go easy, and have it clamped down good.) and tap one side of the advance plate for a 1/4" pipe plug. I put the plug in with loctite and grind it almost flush on both sides.
I then drill to size using this chart. Note, only do 1 side or it doesn't work right.

Modifying advance slots
degrees / slot size Double for Crank Degrees. I usually start with a 19/64 , or 5/16 drill bit. For 4 or 5 degrees (8 or 10 crank)
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