New Build 340/420 Questions

YO7_A66 said

I opened up my distributor last night to replace the springs and found a broken rotor tab, loose and rusted small spring, and a crack in the outer aluminum housing.
I ordered another Mopar unit last night that has VA. This weekend I will start setting up the new unit. I am aiming for 22-24 initial, 32-34 all in by 2800-3000, and maybe the VA in the mid 40’s for a start.

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Just because I have issues, can you tell me the rpm you are shifting?

I'm going to say that 32-34 at 2800-3000 is in pretty early. I'm guessing that your torque curve is starting to flatten out right there and probably peaks at 3800ish. Maybe a bit higher.

You need less timing at peak torque. So you'll fight tip in rattle and probably end up retarding the timing to stop it.

Then you add in the VA at cruise and it gets worse.


IMO you need to slow the curve down to get the timing at peak torque down to 24-26. and by peak rpm you can be in the low 30's for total.

Also, you should drive the car with a vacuum gauge. Watch what you have for vacuum at various loads and throttle position. You can then work out the VA timing.

Depending on your gearing, engine coolant temperature, spark plug heat range and such you may have to delay and/or reduce the amount of VA the vacuum can adds.

It's a process and it takes some time but it's well worth it IMO.