AJ said:
The biggest cam I have run is the old Mopar 292/292/108. ...and never needed more than the Accell square-top big yellow SuperCoil...
I had a 6C for 20 or so years with the above cam and Accel -003 (iirc the PN) coil. It was certainly a good starter-upper!
BUT...that setup suffered from a problem it took me years to sort out. Every once in awhile, it would start running 'fer shite. Bad. BAD...as in barely get down the road bad. I could accelerate fine, decel fine...but a constant pedal got me tons of misfiring/stumbling/bumbling mess. Several times on the side of the road I changed all the plugs...which would get me going until the next time it happened.
Also...that build had a detonation problem at cylinder-fill time (right around 3300rpm) that I could not get rid of without running racing fuel. It was a 10:1 engine.
The 6C failed twice, the first time sent back to MSD to be repaired. The second time it quit, about the 25 year mark...idling in my driveway. I put in some old 5-pin OEM box I had lying around. OK-fine.
AND...the detonation problem disappeared.
I asked questions about that over and over...of MSD, 3rd party repair outfits, wrenchers I knew. None of them had an answer for the MSD causing a detonation problem. Most said (including MSD), 'That can't happen.' Except...it did.
The stranded on the side of the road part? I am convinced in these later years that it was a coil overheat problem. It was those years later that someone on this forum (AJ or Mattock I think) said that was likely the issue. The engine feels like it's experiencing a vapor lock problem. I had NO idea back then that a hot coil could act like vapor lock. Ballast resistors were of the proper/specified value for the setup being used at the time. As in...MSD says 'none', but the -003 Accel power tower says 'only ours'.
Have not had that issue since running an OEM style sparky box (of several different makes..Standard, NAPA).
While the fast cold-starts were nice...changing plugs on the side of the road on a hot engine with Hedman headers with the convenient hi-crossover tube that makes #5 tricky, is something I could do without.
I would sure like to know...for a fact...why the MSD6 caused that detonation problem.
It's a cute red box. Looks cool. Years of trouble and problems.