First make sure your pinging is not caused by the following:
1) Low octane gas with such a high CR, try super unleaded with octane booster
(non-methanol), or racing fuel.
2) Vacuum leaks, could be anywhere.
3) Too weak a mixture, your needles may be giving you a weak mixture
which will cause ping, since the needles are profiled, they may be too weak
only at certain rpms.
4) Cam timming might be off, easy to do especially if your new cam needed
to be set at differrent timming to the original.
I would look at the dizzy advcance curve after you have rectified the above.
Then get a set back timming gun and see what your advance is at different
rpms, say at 500 rpm intervals and pay special attention to the total
advance you are getting when you get ping. Compare this to the advance
curves you have for the non-emission dizzy and see if yoiu are really
that much advance.
Try setting the static timming progressibly closer to TDC and see when the ping
goes away, this will tell you if it is the dizzy advance. If you still
are convinced that the dizzy is your problem, you will need to
take your engine to a place with a dyno, have them calculate the best
advance for your engine set up, send off these specs (i.e., degrees of
advance vs rpm) with your dizzy to Jacobs electronics and they will
recalibrate your dizzy. If you ever change your engine specs, chances are
you will need to have the dizzy recalibrated.
Jacobs also make a comuter unit that you can custom dial in advance curves,
this is different to their stupid little advance box. You then bypas
your dizzy and pick up off the crank or dizzy with the base plate fixed.
I STRONGLY recomend you check out 1-4, chances are your carb needles are
WAY off, totally way off, especially if they were from an emission controlled
car, as these ran lean and lean running will cause ping especially at
high CRs.
You might also try cooler running plugs. Maybe get fancy and use a water
injection system to cool the inlet charge and therefore the combustion
chamber which again should help.
Jacobs should have a web page, otherwsie i can dig up their number.
Cheers Dennis
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