Hey guys. Me and my friend have exactly the same distributors in our cars, Pro-form new units. Mine is a 350, his is a 454 Chevy. Both of us are experiencing exactly the same problem, slight miss over 5500 that turns into major miss you can feel and hear just about 6000 RPM. Our plugs/wires are new and good, and it has been doing it with previous set of plugs wires. We are thinking it is possibly our ignition modules. They are stock replacment ones. Does this sound correct? I have a Digital ignition box I could try out, but he wants to stick with the module and says that a "corvette" module is good to 10,000 RPM. Any thoughts on this guys? Thanks.

 

I doubt it would be the module since a faulty module would be noticeable at start up, What it does is send pulses to the injectors, Are u having trouble at start up?

 

A "good" module does improve high rpm ofcourse. Longer dwell time, stable ignition, faster coil saturation rates all extend the rpm range. But don't overlook the coil, a higher voltage coil can eliminate those misses too, overcoming the air turbulence at those rpms. Or an add -on box like MSD 6AL.

 

Module could be heatin up, and missing pulses because of it.....I had high-rpm problems like yours and they went away when I changed to an Accel module and coil. That's with an early HEI setup.