Hi fellas, thought you might like to see my HEI conversion mounted inside the shell of a busted Mopar ignition box.

I did it this way to maintain stock appearance and loom connection.  There's a jumper wire hidden behind the ballast.  To convert back to Mopar ignition in an emergency I can simply cut the wire and plug in a Mopar box. 

The module backs onto the Mopar heat sink with a layer of heat conducting grease inbetween just to be on the safe side.  The Mallory module was about $25 but you can get unbranded ones as cheap as $17.

What do you think ?

The advantage is that the HEI module has current modulation instead of being just a big switch.

Current modulation powers up the coil only until the coil is saturated, then it pulls back on the current.  That way it doesn't need a ballast resistor to avoid overheating itself or the coil and without a resistor the coil can charge to higher voltage and faster.

Basically, you can run any coil with it and any coil you put on there will run at it's optimum.

With a low impedence performance coil it can deliver 50 + kv at the plug.

I already had my Accel coil, but a good budget coil to use with the HEI is the Ford TFI coil - it's one of those "E-core" things.  Apparently they were fitted on millions of US Fords so there are plenty in the junk yards over there (but not over here LOL).

I can't take all the credit for the idea of hiding it in the box - I saw someone on another forum who had hidden one in a Motorcraft box.  I think I may be the first person to hide one in a Mopar box though.

Only bad thing is they may heat soak and develop misses when run at or over 6500 rpm for extended periods of time.

Only bad thing is they may heat soak and develop misses when run at or over 6500 rpm for extended periods of time.

I've read that heat can be an issue with these....wonder if a CPU cooling fan would fit in the "BOX"

I don't think heat will be a problem for the driving I'll be doing.

You might get a fan in there but If I needed to improve the cooling I would say the best way would be to sandwich a nice slab of aluminium in behind the module as an additional heat sink.  There's plenty of room for that.

Just for laughs though, a CPU fan would look goofy stuck on the outside.   

                  I"M ALL IN 

Has your challenger got a factory tach ?

My tach reads a bit funny with the HEI.  I've seen references to a "filter" you can put in line with the tach wire but I'm not sure what it is - I suspect it could be just a big zener diode or some other quite simple thing.

yes mine has the tach,,and it seems to work smooth but runs like it may be off alittle,,,when running at 70mph it sits at 4k