<VV> Ignition Help

[Dennis & Debbie PLEAU]

I went to Montrose, CO for the annual Tri-State meet.  It's about 275 miles 
each way over the top of the Rockies.  No problem getting to Montrose, but 
on the way back going up towards Monarch Summit (11403')when I had to shift 
dow to 3rd, the van started missing.  It made the summit and then started 
back fireing out the exhaust on the way down the other side for a while and 
then quit.  I missed all the way home from there.  It seems to be ignition 
related as I don't think it is one cylinder or one bank.  Iyt also seems to 
be temperature or load dependant.  The higher the RPM the more it misses.  I 
could go long streaches at 60 mph with very few misses, but it I ran 65 it 
started missing big time after a few minutes, which also leads me to believe 
it is also heat related.

I'm guessing it is a coil over heating or a Pertronmics I failing.  I have 
both the Pertronics and the Flame thrower coil running on 12 volts.  It also 
has a really old cap and rotor.

Let me know what you think,

Thanks,

dp