I have a 408 small block with a electronic Chrysler distributor and the mopar light springs. Vacuum advance not hooked up. When I try to time the engine even at 1000 to 1200 rpm the distributor advance is in the recommended 34-35 degrees already. Then it will advance further if it is opened up. I also have a distributor that I put both the lighter stock springs in, it will be at about 30 degrees at 1000 rpm. Everything I read is that 34-35 deg. is supposed to be the all in number when the engine is at high rpm and at idle it is supposed to be around 10 degrees or so. So how do I know if I have too much timing? These distributors have a lot more advance in them when the motor is opened up. The one with the slot and weights seems to have more than the later one with a slot and tab. With open headers there is no way of hearing any detonation. How do you guys set timing on a chrysler distributor?

I weld the advance slots up on the stock non adjustable distributor so I can have 12 to 16 degrees initial timing at a low idle, 600 to 800 RPM and then have a total of 34 to 36 on Mopar BB. All the SB Mopars I help tune and race with iron heads seem to like 30 to 32 degrees total. If you take that distributor apart you should see a number stamped onto the top part of the distributor that the rotor fits onto and the advance weight pins ride in to make the mecahincal advance It should read between 10 and 14, those are the distributor degrees, not crankshaft degrees. Distributor degrees are twice as much as the crankshaft degrees so that means if the number is 12 you have 24 degrees of mechanical advance if it is stamped 12 distributors degrees and you want to have 32 degrees total due the math and shorten up that slot so you get what you want, IE 14 to 16 degrees initial timing and 7 degrees mechanical equal 14+14=28, 16+14=30, 18+14=32 Let us know what you do

Yes that is the procedure I have read. But what do you use for springs so that it is not all in (34 deg) at 1000 rpm? That's what mine seem to do. Any stronger springs and it would just be a guess if they would come in fast enough or all in for a race engine. I have a later one with the tab slides and set screw adjustments like the MP ones. Thanks for your reply.

I like mine all in by 1200 to 1500 RPM ( on BB and 426 hemi motors) Try using two of the smaller diamerter stock Mopar springs instead of the real weak race springs if you don't want all the advance in before 3000 RPM