Pertronix fix for 300 six

[sargentrs]

The one for the '76 with a 390 will work just fine. The WPS brand is the brand I bought for my small block. It's brand new, not a reman. For the ICM, I prefer Standard Motor Products to Airtex. The LX203 has the blue grommet like you want. For the coil, I'd get the SMP FD476, not the T.

[sargentrs]

Also, if the distributor comes with the small cap with female sockets you might want to upgrade to the large cap with the added adapter and male pins. That is if you have room. You can also upgrade to 8mm performance plug wires and increase your plug gap to .040-.042. My small block ran fine at .035 though. Don't be surprised if you need to increase your timing a couple of degrees. I went from 10* to almost 14* on my Fairlane and she loved it.

[colnago]

Randy,

Thanks for the tips! With your help, I should have a Duraspark under the hood this spring (assuming that I get off my rump and finish the rebuild).

Joseph

[colnago]

Randy,

Just placed my order! Looking forward to putting it all together this spring. Again, thanks for the pointers.

Joseph

[sargentrs]

Are you going to use a relay for power? I'm working on a sketch showing how I wired mine up.

[colnago]

I'm not sure. I haven't thought it completely through yet. A relay should be pretty easy to splice in as I'm putting it together, though.

I'm also not sure where I'll mount the ICM. Right now, I'm thinking passenger fender. Maybe in the cab. Probably not the firewall. Decisions, decisions ...

Joseph

[sargentrs]

That's the great thing about using a relay, you don't have to splice into your original wiring. I mounted my ICM laying flat on the large horizontal surface of the inner fender. The mounting holes are threaded so you bolt it from the underside up. Lay it down, mark and drill the holes and clean up the underside of the fender where the holes went through. You'll want to space the ICM up off of the fender about 1/4" for air flow. They hate heat and vibration and it's the most common cause of failure, although I've never had one fail. You can cut some rubber hose or use rubber washers or grommets. Grab some star washers, put them on the bolts (1/4" coarse thread about 1" long) and and insert them from under the inner fender up into the box and snug it down. Here's a couple of photos. The first one shows the location I used for mounting the relay on my Fairlane. A similar location works on a bump, maybe laying flat on the inner fender. That gives you easy access to the battery and to the solenoid. The 2nd photo shows what I think is the original mounting of the ICM on a dentside. I'm still working on that sketch of the wiring and I'll have that posted by the time you're ready.

[sargentrs]

Here's how I wired my Duraspark. I installed the relay next to the solenoid and wired a red 12Ga wire to relay terminal #30 through a 30A inline fuse to the + post on the battery. My battery cable had the extra wire coming from the clamp which was handy. I drilled a 1/4" hole in the inner fender and used a black 14 GA wire from terminal #85, on the relay, to a 1/4" bolt with star washers and a lock nut for ground. Starting a couple of inches from the 3 prong connector for the ignition, water temp and oil pressure, I cut the red/green wire and installed a female bullet connector. I put a male bullet on the piece I cut off and coiled it up and placed it aside. I then fabbed a 16GA green wire (green so I knew it came from red/green wire) with a male bullet on one end and a female spade on the other and ran it from the 3 prong plug to terminal #86 on the relay. Then I fabbed a red 16GA wire with a female spade on one end and a ring terminal on the other and ran it from relay terminal #87 to the + side of the coil. I did not use relay terminal #87A but it's there if I ever need another switched hot source. I stuck an insulated spade terminal over it to keep anything from accidentally touching it if it's hot.

Moving on to the harness, I bought 16GA wire in all the colors shown in the diagram for the ICM and distributor harness. I started with the 4 prong plug for the ICM to the 3 prong plug on the distributor using an SMP HP4735 (4 prong) connector and a SMP HP3935 (3 prong) connector I bought from Rockauto. The pigtails on the plugs are black but you can match terminals to wire colors from the diagram below. I left the green wire loose, no tach, and just taped it to one of the other wires. I fabbed a harness from the 4 prong to the 3 prong and plugged it into the ICM. When I went to plug in the distributor I realized that the locking tabs on my Rockauto plug weren't in the same location as the distributor plug. I took my pocket knife and shaved a little at a time off of the tabs until the plug slid in securely and then put some black tape around it for safety. The 4 prong plug was a perfect fit.

For the power source at the 2 prong plug on the ICM, used another SMP3935 (3 prong) plug and just didn't use the 3rd terminal, taping the loose wire to one of the others. This plug had the locking tabs oriented correctly to match the ICM plug and the 2 parallel terminals matched perfectly for a good, secure fit. I fabbed a white wire (16GA) with a ring terminal on one end and spliced it into the white wire from the plug. I ran it to the "S" terminal on the solenoid, leaving the original red/blue wire in place. I then fabbed a 1 in - 2 out wire using red 16GA and a "T" connector. I spliced this wire into the red wire at the ICM and then made 2 other wires with ring terminals and spliced them into the "T" connector. I ran one to the "I" terminal on the solenoid, leaving the original brown wire in place, and the other I ran to the + terminal on the coil. That makes 2 wires to the + side of the coil., one for the "I" terminal on the solenoid and one to power the ICM from the relay. Not exactly sure if that's how it should have been done but it works. And of course, black wire from the dizzy to the - side of the coil.

After I made sure it worked, I replaced my plug wires with 8mm performance wires, new spark plugs and dialed in my timing, upping it a few degrees. She ran great!

All wire splices and terminals were done with uninsulated connectors, crimped, soldered and covered with shrink tube. I had a couple of small spring clamps nailed to my workbench, as a soldering jig, and sat there for hours making wires Once I had everything installed I went back and covered all of my wiring with some 1/4" and 1/2" braided nylon sleeving I got from Summit Racing. https://www.summitracing.com/parts/sum-890340 Really nice wrap. Braided nylon, split and wraps back on itself. I took all of the old points stuff, dizzy, cap, rotor, wires, ignition wire from the harness plug and made an emergency points install kit. Hope this helps somebody out!