I started having spark knock when i went to 87 octane gas in my 71 Dodge truck ( stock 82 225 clifford split header proline dual weber setup and msd 6al ) so I decided to retard my timing a little but it still had spark knock so i decided to look at the weights and change them if neccasary.
My distributor is a mopar performance unit that i bought last Oct. When I opened up the dist. I found that it only had 1 spring for the weights so i added a heavy one from an old points dist. I had laying around and that helped but I still have a small amount of knock when i smash the pedaL in high or o/d ,do i need to weld the slots in the advance or is there somthing else i can do? Right now I have 35 degrees total advance and 10 degrees initial and thats with the vacumm advance hooked up and dialed in per Mopar Performance instructions.
Thank you,Mark

_________________
Ive got a slanted attitude and a heavy right foot.

You should target 30 to 32 degrees total advance, all in by around 3000 RPM (give or take a little)

Either weld-up a slot or tighten the heavy spring a little. I find it is better to have the heavy spring stop the advance instead of having the weight(s)bottom-out in the slot, when they bottom, sometimes you get high RPM bounce.
DD

Thanks Doc, I dialed my dist in and the truck is much better now ,pulling 32 degrees all in at about 2700 rpm with 14degrees initial.I also swaped the stock Caravan muffler for a 2 1/4 glasspack and it really cooks now and my mileage is better too.
thanks ,Mark

_________________
Ive got a slanted attitude and a heavy right foot.