Hi Guys...been quite awhile since i posted.Just going over this distributor from Rock Auto...DST3890
The mechanical advance slots are .410 which should be about 11 x 2 degrees total mechanical for 22.This should allow 12 - 14 initial and a total of 34 - 36 right out of the box!
Has anybody checked the rate of mechanical advance the stock springs provide?
It also has some other nice features like only one roll pin position and no spring lock but a screw instead.

I didn't go to their site to check it but just me I would suggest a 70's OE electronic dist & the FBO $22 plate to set the mech amt where you want it & you can dial in the initial the springs & the can & reduce lower shaft axial play, reduce rotor tip clearance & check rotor phasing

Tx RR...i'm no stranger to curving a distributor be it weld the slots,change the springs or whatever....These springs are not factory style 2 stage and look to be fairly stiff.I was wondering if anybody has mapped the curve?

I'll go there sometime & check it out.

..finally tested the distributor.Initial was 15 and by 2000 there was about 22 degrees advance having full advance of 35 degrees around 3600 rpm. ( Initial plus mechanical )This is a very slow curve and would be very helpful if you're fighting detonation in a high compression sm block.Single stage springs are loaded initially and adding 1 weak spring should work great for
a street machine to bring advance in quicker.
no welding of slots etc.

At $39.79
It has a scary cheap price...

i agree...but it appears to be a very nice piece! I think Rock Auto has them for about $50.
such a deal!