HEY GUESS WHAT, ME TOO.
Hey guys ive been their with the same problem .I chucked a blue top in my AE85 and Tried to be clevier and used the 3AU Dizzy then the fun began.
It would start a treat but give it a ring and would run sluggish and back fire.
I was running cams so advanced the timing to get it to idle but had to get a larger battery to crank it at start.
Coz of the fact that when it started the dizzy would go to advance machanicaly but in reality was retarding the timing and the higher the RPM rised the timing progessivly retarded reducing the power and increasing the back fire issue .
This had me stuffed for a bit because I was told that the 3AU would work
DIRTY LIAR!
I thought about it for a bit and sussed it out .Gutted the dizzy and modded it to advance in the other direction, not fun .
I would'nt recomend it.
I binned it coz the ignition curve was all bundy.
So now im using a 4K Dizzy,It advances in the right direction.
It requires some fabrication /modification but is the real deal.
Ive used a points type its good for 8K but the electronic version would be better.I now know of two guys rallying the same set up through friends.
The ignition curve is good so ive been told
I can help with the fabrication measurments if ya want them give me a heads up at.
skdtoy@hotmail.com