ignition questions

when should i start thinking about upgrading from the MSD 6aL boxes to the 7 series stuff??

im going high compression, large cam, good heads and the like, so should i start looking into the 7 stuff to deal with the new demands of the engine?

For what my opinion is worth, the MSD 6 Series ignition boxes will go a long way! I think a few considerations in deciding to "step up" to a MSD 7 Series ignition box would be high compression and/or high engine speed. There are other considerations like cylinder pressure levels and fuel volume inserted into the combustion chamber. In layman's term, if the candle tends to go out, you need to turn up the wick!

Just mu $0.02!
Dave.

How much C/R, and how fast? If in doubt, you probably need a 7 series iginition.

13.3:1 comp and in the 10's

Should have worded that better, how many RPM's?

I've ran mine at 16 to 1 and 7200RPM with a 6AL and a 7AL3 at 8.70's..Couldn't tell any difference with either box ?I'm not sure how far you got to go before it matters?