carterb Posted February 22, 2014 Report Share Posted February 22, 2014 Anyone have a picture of the stock mounting location for the ignition control module in a 78 620? The mounting holes in the kick panel of my truck don't seem to jive with the parcel shelf. Thanks! --carter Quote Link to comment
jastrunk97 Posted February 22, 2014 Report Share Posted February 22, 2014 Here you go, this is was mine looks like. Quote Link to comment
carterb Posted February 22, 2014 Author Report Share Posted February 22, 2014 thanks. So yours is just haging by one screw then? In your photo, the hole to the bottom right is where the other ear mounts, but it is covered by the parcel shelf. Quote Link to comment
datzenmike Posted February 22, 2014 Report Share Posted February 22, 2014 Yup that one is too low. Mine was behind the dash and just barely visible. Still works. Quote Link to comment
jastrunk97 Posted February 23, 2014 Report Share Posted February 23, 2014 You cant see mine when sitting in the seats. I just took a photo with a really low angle Quote Link to comment
carterb Posted February 23, 2014 Author Report Share Posted February 23, 2014 Yup that one is too low. Mine was behind the dash and just barely visible. Still works. Behind the dash as in - mounted to the firewall? Quote Link to comment
Laecaon Posted February 23, 2014 Report Share Posted February 23, 2014 On the kickwall. Up in the dash area. I remember accessing one through the glovebox, well sans glovebox... Quote Link to comment
difrangia Posted February 23, 2014 Report Share Posted February 23, 2014 Exact project that I'm working on at the moment. The module on my 78 longbed went out over a cold spell that we had a couple weeks ago. It sat for several weeks while I drove a couple other cars and when I went out to start her about a week ago; no fire. I checked it all out, referring to Ratsun in the process and decided to do the GM module change-over. I hotwired one in yesterday and, Viola, fired right up and ran better than ever. I'm gonna do the permanent mount today. Probably gonna mount it on an aluminum plate (heatsink) where the original module was at top of right kickpanel as shown in photo by OP. I think I like this so much that I'll be looking at incorporating the late 70's non-matchbox dizzy & GM module into the rebuild of the E1 engine in my 320 pickup. I believe that Mike K detailed the dizzy change-over in one of his write-ups. This just has to be one of the most informative and helpful forums that I visit for the varied interests, hobbies, endeavors that I have. Thanks y'all. By the way, I checked on a Nissan module and it was about $200. Gave about $20 for the GM unit. They can be had for $15 or less on Ebay. Steve Quote Link to comment
heretic Posted February 23, 2014 Report Share Posted February 23, 2014 both of my 78's have it mounted just like the pic Jastrunk97 posted. passenger side right above the parcel tray. 1 Quote Link to comment
datzenmike Posted February 23, 2014 Report Share Posted February 23, 2014 The HEI is mounted inside a GM dizzy with little air circulation so mounting anywhere outside is fine. Maybe a small aluminum plate with 'legs' to raise it slightly above the inner fender. There will be more than plenty of air circulation from the rad fan. Mount beside the coil and tape the wires and cover with that split harness covering for a neat look. You can also get a dab of silicon heat sink compound from a computer store. Quote Link to comment
difrangia Posted February 23, 2014 Report Share Posted February 23, 2014 Completed the GM HEI module install this afternoon with a little help from a great big dirty martini. Here's the original with connector unplugged. I made a base plate from 1/4" aluminum for a heatsink using the original module to establish mounting holes. Broke out the solderr & heatshrink and made up little pigtails to connect the new module with the original connector on the loom. Mounted the module to the baseplate using the heatt transfer grease that came with the new module. Mounted the new assembly back in the original location and plugged in to priginal loom connector. Then a little buzz about town to celebrate with a big smile on both my face and also the little 'Longbed's' face. Steve Quote Link to comment
difrangia Posted February 23, 2014 Report Share Posted February 23, 2014 Forgot to add in last post: the procedure is reversible in ten minutes or less. Just unbolt the unit and put original module back in, if available, and plug back in. No wires were cut or changed in changing to the GM module. 1 Quote Link to comment
carterb Posted February 24, 2014 Author Report Share Posted February 24, 2014 Cool! I love it when you get more than you asked for in a thread. Quote Link to comment
Laecaon Posted February 24, 2014 Report Share Posted February 24, 2014 I did something kinda similar. I had to figure out the spark on a 620. Well a Matchbox dizzy in a 78 caused the issue. Traced the wires. Made 2 jumpers at the missing box. And wala, the truck was wired for a matchbox. I think I jumped the green to Blue/white, and red to black... or that is backwards. Quote Link to comment
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