I have a Mallory 47 Series Unilte with vacume advance, Mallory 29216 coil, Mallory Hyfire IVa ignition box, 8mm Accel spiral core wires and Accel plugs. I have the plugs gapped to .035. The coil is listed as working with the hyfire IV boxes. Problem is when I get to 4000 rpm or so the engine stops pulling and won't wind out. It is also missing at 40 mph cruise. When I install the Hyfire ignition box bypass wireloom problems go away. Also, when the box is running tach doesn't work and when on the bypass it works fine. There is suppose to be some sort of tach adapter (29074) has anyone had to install one and will that fix the tach problem? Does anyone run a simular setup and have problems or past experiance and know the fix? Thanks, Jeff
