Blew muffler all to H,,ll

[300]

Well, got new build done(70 Cuda 340 sixpack). Everything is new. Had the engine builders here and after the start up shut it down to make some adjustments. Went to start again no go no spark. Again and again same thing (Has MSD Digital box) Anyway after about 6 try's Boommmmmmm. Blew the back of one of the mufflers right out and what was a AAR one is now a round nothing( can,t hear out of left ear good as the pipe exists in front of rear tire, On the phone to MSD they said bad box it was only giving intermediate spark causing to much fuel in bowl and exhaust ( YA) also said to disconnect ballast resistor although my friend that works on Mopars and does MSD wiring had it hooked up, (He wasn't,t here for fire up). Now have to order new AAR mufflers and wait for new MSD box, and try this another day. Wow what a fun day

[brads70]

Bummer! I want to hear/see that thing of beauty on the road! 

[dodj]

If the MSD was wired with the ballast resistor in cct, it won't work properly. MSD box needs 12vdc, the ballast resisitor drops the voltage to like 9vdc.  Take  the resistor out of the cct before you fire up with the new box.

[Chryco Psycho]

the ballast will have a blue & brown wire , the red trigger wire for the MSD Must be connected to both the blue [12v run ]& brown [ 12v start ] wires to work .

[300]

Thanks I,ll give that a try. We did hook up the wires as you said,but I guess the box was junk by then