[Gmecm] Gmecm - Does anyone know if there are any tricks to using a big cap HEI on a 747 ecm?

[Mark Romans]

Gmecm - Does anyone know if there are any tricks to using a big cap HEI on a 
747 ecm?

I have a friend who put a 747 ecm in his 80 Buick and is running a big cap 
HEI and a 747 ecm.
The Car runs great with the EST Bypass disconnected, except it doesn't have 
any power due to low timing
advance in the module, when he hooks up the EST bypass the timing jumps all 
over the place.

I don't think it's in the chip because I smoothed out the spark map where 
the idle is, and even when the timing
should be staying constant it's bouncing all over the place.

The order of the wires between the small cap and big cap HEI are reversed 
and I have checked everything to death!
Is there anything I am missing?

Thanks!

Mark