428 Carb Set up

[CJ428CJ]

Todd,

In answer to your questions:

1. I have my timing set at 24 initial and 40 total all in by 2000 rpm's (light blue and light silver springs, black stop bushing). That sounds like a lot of timing awful fast but it works great and I get no pinging or run on after I shut down. I did double check my timing mark with a piston stop because it seemed like too much timing to me too. I have the aluminum heads which allows more timing. If you have the cast iron you may not be able to get away with that much advance.
2. No the Demon was not custom built. Bought it off the shelf.
3. Compression is 10.25:1.

Have you checked your vacuum with a gauge yet? Having a PV too high can cause it to run way rich (the PV opens at idle causing a really rich condition and then people open up the idle butterflies to get enough air in to allow it to idle - but damn near knocks you out from the fumes).

All I did to optimize the timing was to play around with it a bit. In my opinion, a light car with a large engine will want a lot of advance as soon as possible. As long as you're not getting any pinging or engine run on when you shut it down, then you don't have too much advance.

Also, any carb adjustments that you do (other than the final idle adjustment) should be done with initial timing set at 25-30 BTDC (per the instructions I got with my Demon) even if you have to retard the timing a bit before you can actually drive it (to avoid pinging).

Chaplin, I wonder if advancing the timing will help your situation too.

Chris