You can swap the points style out for an HEI. Just take out the old and put in the new. The points style has two wires that power it, one 12 volt from the starter that is only hot when the starter is engaged [yellow on 68], and one about 9 volts that runs through the resistor wire from the firewall junction box[pink/black on 68]. The resistor wire is hot when the ignition is on. That provides 12 volts to start and a lower voltage when running. An HEI requires 12 volts at all times. Remove the wire from the starter and replace the resistor wire with a non-resistor wire. Or put a solenoid [relay]near the distributor using the resistor wire to switch it on and off, and a good 12 volt source to power the distributor through the solenoid. I power mine through a solenoid and have 14.8 volts at the HEI when running. The HEI has a larger circumference than the points distributor and has less clearance at the firewall but mine fits no prob. Sorry I don't know the colour of the wires on 67/69. You can try googling "Hot rodding the HEI distributor" I have it but don't know how to attach links.
I recently have upgradeed to HEI I got a pertronix flame thrower. It is a nice addition but it's a super tight fit. I matched it with a new set of msd wires for a 74 TA lengths matched up perfect. The install did not go smooth as I would have liked but that's a whole other story. it was worth the switch in the end.
Good info, should get you there. I would use a GM HEI rather than aftermarket, just my opinion. Many have aftermarket and really like them. If you do go aftermarket try to avoid the MSD "ready to run" distributor. I had so much trouble with one I sent it back and got a used GM. "ready to NOT run"
I use a relay to power the HEI, it can get you more voltage at the distributor, and you don't have to remove the original resistor wire, 9 volts will switch the relay. If you ever want to go back to pure stock the wire is still there. After installing a 140 amp SI alternator, my dash volt gauge still showed only 12 volts. I checked the voltage from the alternator through the firewall junction box, to the ignition switch and from there to all the components and lights. Voltage drop was amazing. I had 14 volts at the alternator, 13 volts at the junction block, 12 volts at the ignition switch, 11 volts at the light switch and only 10.5 volts at the headlights. there was a bit of a voltage drop at every junction. 46 years of age, dirt and corrosion. I've since cleaned things up and replaced a few things for better circuits. I did run the power wire for the ignition relay from the main power source off the alternator and get 14,8 volts at the distributor. One case where more really is better.
Good info, should get you there. I use a relay to power the HEI, it can get you more voltage at the distributor, and you don't have to remove the original resistor wire, 9 volts will switch the relay. If you ever want to go back to pure stock the wire is still there. After installing a 140 amp SI alternator, my dash volt gauge still showed only 12 volts. I checked the voltage from the alternator through the firewall junction box, to the ignition switch and from there to all the components and lights. Voltage drop was amazing. I had 14 volts at the alternator, 13 volts at the junction block, 12 volts at the ignition switch, 11 volts at the light switch and only 10.5 volts at the headlights. there was a bit of a voltage drop at every junction. 46 years of age, dirt and corrosion. I've since cleaned things up and replaced a few things for better circuits. I did run the power wire for the ignition relay from the main power source off the alternator and get 14,8 volts at the distributor. One case where more really is better.
Hey Bluebird, would be interested in seeing like a wiring diagram on how you ran all that, you by chance have one? I like the idea, I am just still a little confused on how you ran the wires and is the only purpose for doing it the way you did was for more voltage to the HEI? Also, do you have A/C and a lot of extras for using a 140 SI alt? What 140 Alt do you use? Sorry, not trying to hijack!
A wiring diagram is on my to-do list. I will have to take drawing lessons first. I have twin electric radiator fans, my voltage dropped a lot when I turned them on so I installed the Powermaster 3 wire alternator. It helped a bit but the voltage was still low so I checked it everywhere and discovered the voltage drops. The voltage regulator, internal or external, has a sensing wire. That wire inputs the circuit voltage, if the voltage is below 14.2 or so the regulator ups the alternator output, if the voltage is above the set voltage the regulator lowers the alternator output. Trouble is the sensing wire is connected to the soldered buss which is close to the alternator output and in a location that does not suffer from voltage drop. It keeps the battery charged but does little to detect voltage in the trunk. If I had connected the sensing wire to the ignition switch it would have sensed the lower voltage in the dash area and raised the alternator output. I already had the new alternator installed when I discovered the causes of the low voltage in almost every circuit in the car. When I pulled the engine to repair the rear seal for what seemed the umpteen time I removed every wire under the hood, save the ones attached to the windshield wiper, and made my own harness. I used heavy gauge wire and crimped, soldered then heat shrink wrapped every splice and connection. I installed a terminal block on the firewall with # 8 wire from the alternator and that is now my main buss supplying power to the dash area, the ignition relay, and the battery. It's also a convenient place to attach any accessories I may want to install. I ran a #8 wire to a second terminal block attached to the rad support and this is the buss for the fans, horn and headlight relays. Originally the headlight circuit went from the alternator, through the firewall junction, under the dash, to the light switch, to the dimmer switch, back out through the firewall junction, and to the headlights. Now juice goes from the terminal block to the relay and then the lights. The difference in headlight brightness is amazing. Obviously my car is not stock but most people who look under the hood do not notice the changes. Sorry for the long winded reply. You can wire in a relay by supplying battery voltage for the main power input and the stock distributor wire for the control [switch off and on]. It would be a good idea to put a fusible link or 10 amp breaker between the battery and the relay. A typical Bosch style relay will have the power from the battery going to the input terminal #30, the ignition wire to the switching terminal [off/on] #86, output # 87 terminal to the distributor, and # 85 terminal to ground. I ran the ground wire from the relay to the mounting screw but it may be a better idea to run it to a ground on the engine block. An HEI will put out more if it has a full 12 volts even better with 14+ alternator output volts. I you are getting good voltage to your distributor you don't really need a relay, but putting in a relay and fusible link or breaker sure won't hurt.
Don't Do HEI, That's old tech!.... Go with a MSD ready to run distrib. Check out my build thread for pics. You don't need the box. I added it for more of a complete burn.
IIRC I used the Pertronix 1 unit with zero problems so far and I believe it has been three years. I installed it just like the instructions without any extra wires or hookups to a 12V source. The motor runs significantly better and the throttle response is crisp. I am going to take some black shrink tubing to mask the blue wire to make it appear OEM. Its the only extra wire in the unit and is hard to tell unless you're looking for it. I think I spent $80 on eBay.
Just read your article. I changed out my 68 from points to hei about 12 years ago. I put in the Mallory Hei Kit. You pull your distributor, disassemble and pull out the points and install the new Hei kit inside the original distributor. It has 3 wires that come out of the distributor base vs. the single original style. I wrapped the loom with factory style cloth tape. The only thing you will want to add is Mallory makes a voltage spike filter. I did not purchase this originally and when I hooked the battery up one time it arced and fryed the module in the distributor. Put the filter on and no problems since. total cost at that time was about 120.00. I really liked this option because you retain the smaller style distributor cap in an already cramped engine bay.
Does the tachometer continue to work and/or is accurate after the disti is modded to run on the Pertronix modules?
On some Mustang forums there are posts complaining of tachs not working after the change... and reports Pertronix Technical Support advising they are aware of a problem with analogue tachs (not sure if this is just Ford tachs).
Hi guys, I realize I'm a little late to this thread by about 6 years but I wonder if anyone can share a part # for that 12 volt relay? I'd like to get one.
