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Discussion Starter #1
Can anyone tell me where to find information about performance mods for GM HEI Distributor #1103216 - 5k15. It works fine now but while I have it out just wanted to know if there are any enhancements to make it better, i,e, electronic pick-up, coil, adjustable vacuum advance, etc. It does not appear to have any mechanical advance weights or springs.

Thanks, Roqetman.
 

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R you can buy a Proform HEI rebuild kit...all the party's houses Pontiac houses have them, includes weights springs and Vacumn advance...all which you need unless it is just a race car.....

Of course that 65 did not have an HEI, those came in from 75 to 86....you could also go back to original rebuilt dizzy....parts houses have them to, and a separate coil.....

Good luck cool car,......
 

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Discussion Starter #3
Thanks for the info. I'll check out Proform HEI. I do not like the old points system... they suddenly burned out left me stranded in my Oldsmobile a few years ago.
 

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I use the original points dissy to fire an MSD unit, it uses resistance not voltage so the points never burn up. Plus the MSD unit gives a better spark, easier starting, better MPG's etc. I hid the unit between the fender and the fender well on a plate bolted to the two bolts right there so everything looks stock. I haven't replaced the points in over 10 years. I happen to have an MSD unit for sale if you're interested. You can see it mounted here before the fenders were installed, I also went back to a stock coil too.

GTO Half Front Photo by Rukee | Photobucket

If it asks for a password it's GTO.
 

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Transistorized ignition (HEI) was an option on GTO's starting in 1964...so it could well be an original unit. I would run it as-is if it is working fine. Points only 'burn up' if there is oil on them or too much primary voltage is run through them. On a properly functioning system, they will not burn up at all....merely wear out after 15k miles or so. I've been running stock points distributors in my GTO's closing in on 40 years, for 100's of thousands of miles without a single hiccup.
 

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R...the distributor you referenced is from a 1976 350 2bbl ......the last three digits after the number you listed will tell you date of Mfg. Coil in cap HEI ignition were introduced in mid seventies,..it had a precursor called TI.......transistorized ignition......but the module was not inside the dizzy then I don't believe .........but maybe someone has one....

rather it was outside like a big box. Coil was external as well. .....Check the walllace racing web for your distributor number........

Your number indicates 1976.....if the coil is in the cap...then it was not from 1965.....
 

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Lemans Guy is spot on, coil in cap is a traditional HEI not found any where near 1965. Is it still worth rebuilding, sure. But if you decide to use a traditional HEI affordable brand new drop ins are out there and with some simple tuning they suuuuure work well these days. Now ill share my .02 on the mysterious and always questioned curve tuning of the typical $79 ebay HEI.

Figure out what total timing your combo likes by test driving it ( a good start is 34 degrees for iron heads ) and also what initial setting does not buck the starter, idle warm or knock. Subtract the ideal initial timing figure from the ideal total that it liked and that is your target mechanical advance. Use and find the corresponding GM center plate and weights from the info i attached below and install it to gain that perfect total mechanical advance for your motor from an HEI. Try to use GM centers only, after markets usually suck. (PLEASE dont weld or braze up the advance slots. That is a hack job and NOT how it is done) Then if you want to play with how fast the new custom tailored curve comes in I have had great luck with Mr Gasket # 928G springs. I use the two lightest gold ones but i have KRE heads that like their 32 degrees of total timing pretty early, iron head motors may not like everything in by 2800-3000 without some ping. End play on an aluminum dizzy should be about .012 to .020, the Moroso kit # 26140 I hear works well to dial this in. I have yet to do it to mine but its on the list while my dizzy is out as I battle my own timing gremlins this weekend. If you want a new trick module Summit sells all sorts with built in REV limiters that work quite well. As far as a vaccuum advance goes many pull 20 degrees in stock form and your motor may or may not like it. It you get part throttle ping with a typical vac advance try an adjustable Accell unit. My motor only wanted 5 degrees from vacuum for cruising to avoid ping on 93 octane the stock 20 degree unit was aweful. Goes to show how different all these motors are. Happy Tuning!


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Been reading here about ignition and seen no mention of the Pertronix set up that uses original distributor/rotor/cap but replaces points and condensor - then add Flamethrower coil for hotter spark. I've used these on a couple engines and they work great, though I still keep points/condensor in trunk in case electronics fail (paranoia?). Does anyone use this? Any disadvantage other than cost?
 

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Pertronics doesn't want/need a ballast resistor. It will require full 12 volts to the coil whereas the points only wants ~8V to the coil.
 
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