HEI upgrade

[BamaDave]

I am wanting to upgrade my factory HEI. MSD makes the 8501 Ultimate HEI kit. Has anyone used it? http://www.summitracing.com/parts/msd-8501/overview/

[Jake Wade]

All you really need is a good AC-Delco or Echlin(NAPA) module and this:

http://www.summitracing.com/parts/du...01bk/overview/


Some lighter springs for the factory advance weights.

Here is a good advance kit:

http://www.summitracing.com/parts/cr...t/model/camaro

Start with two blue springs

[hatzie]

There are lots of myths about HEI. Stock HEI was and is so much better than other stock ignition systems of that time period that many Hod Rodders modified AMC, Chrysler, and Ford Distributors to use HEI coils and modules. My 74 Gremlin had a Prestolite Distributor so I just installed an HEI with the old dizzy gear and drove it. My Wagoneer 360 was an easy conversion to HEI and she was a heckuva lot happier.

Never seen an ignition module that's better than the potted GM AC-Delco unit with heat sink paste to the distributor body for long term reliability. An exposed circuit board in the distributor is bad mojo and power transistors get HOT!!!
A Standard Motor Products "Blue Streak" distributor cap and rotor are good components and they won't break the bank. These are the ones that still have brass contacts.

AC-Delco modules (made after 1979) and the same "later" AC-Delco Coils are a lot of bang for the buck. They pump out 50,000 volts to the plugs in stock dress because the coil is run at 14.5volts and the coil and module are setup to take that punishment. Points used a ballast resistor to run the coil at 6v and many transistorized systems that came out at around the same time stepped the system voltage down to 6vdc through a ballast resistor to the coil. Jacobs actually specified "AC-Delco ignition modules only" saying nothing else was reliable enough.

The fast saturation of any decent quality modern HEI ignition coil is good enough to get you hot spark at 6,500 RPM. I used a Standard Motor Products HEI coil till I bought into the Jacobs CDI multi-spark system. I didn't see enough performance improvement to justify the cost but that Jacobs sure looked cool.

Jacobs 8mm wires look cool and install easy but I'm not sure they're worth the premium price over Belden 8mm wires. Ford Racing makes a reasonably inexpensive set of 9mm wires if you don't mind mixing the Blue oval into your GM.

I've run NGK, Bosch, and AC-Delco plugs on my GM smallblocks. They all performed adequately. The one set of Platinum plugs I ran were no better. Just be sure to get plugs for a 1976-80 and not for your 1973-75.

Re-curving the vacuum and mechanical advance to match your cam will give you the most bang for your buck. See the prior post...

[BamaDave]

How does the ESC module affect the transmission. Can just removing the module completely allow the motor and tranny run so long as I use a stand alone HEI set-up?

[hatzie]

It doesn't on the 85 & 86 models. TBI??? Not sure.
http://www.73-87.com/7387garage/drivetrain/escrepl.htm

[bnoon]

The only reason I went to an aftermarket HEI was because I was having trouble finding a stock one that was still in good enough shape to upgrade. I spent $119 on the Accell that I have now and that included an ajustable vacuum advance (so you can bump initial timing and still not exceed your total WOT timing) and advance/spring kit. If the stock advance mechanism would have been good in the dizzys in the salvage yard, I would have just added those pieces to a stock one.

[ray_mcavoy]

Originally Posted by hatzie

AC-Delco modules (made after 1979) and the same "later" AC-Delco Coils are a lot of bang for the buck.

Just out of curiosity, what's the difference between the AC-Delco modules & coils made after 1979 vs. the earlier years?

[hatzie]

Dwell time and coil resistance.

[ray_mcavoy]

Thanks hatzie!

Is there an easy way to identify the modules made after 1979?

I have several spares that I've saved from old junk vehicles. Most of them are printed with "990" which I believe is the last 3 digits of the 1875990 GM part number followed by what appears to be a date code. For example "6D05". I think that's April 5th, 1976 ... or is it 1986? Any way to tell?

[Tom]

I've ran the super HEI kit back in my 79 with a vortec 350 swapped in. I didn't buy it as a kit though, I just upgraded piece by piece as the truck needed it. I also used an adjustable vaccum advance and changed the weights inside the distributor, but that was because the old 79 gave way too much advance for vortec combustion chambers while cruising.

[MikeB]

I have used that exact MSD kit twice over the years, but it was a lot less expensive then. One distributor was a GM, the other an Accel that I bought around 1994.

I can't say if it's any better than AC/Delco stuff, but I never had a problem with mine. In fact, one has been in a pickup for around 12-14 years! That reminds me -- I need to take a look at the cap and rotor. They may be the originals from the kit.