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What upgrades are worth the money for older GM HEI?

Lil'John

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Title kind of states it. Mainly interested in the coil and maybe ignition module.

Specifically, I have an early 70s Cady 472 that is mostly stock with HEI distributor, a mild cam, headers, and intake running a Q-jet. I need to put a couple of new parts in the distributor for use in the next year when I'll upgrade it to a TBI setup using a 368 EFI distributor(no ignition module). As noted, my main interest is the coil that I could swap between the two.

Is it worth going from a $20 'cheap' Standard Motor coil to a $60+ MSD, DUI, etc coil? Same with the ignition module.
 
The most important part to have replaced / rebuilt is the shaft and bushings.
 
What precision instrument did you measure the runout with ?
 
What precision instrument did you measure the runout with ?
finger.jpg
 
What precision instrument did you measure the runout with ?
I used my precision "did I feel any resistance when turning it" and "did I feel any side to side movement when I pulled/pulled the rotor" tools:homer::lmao:

For the HEI that is temp, I think that was good enough since I'll fight the Quad anyways:homer: For the EFI, I'll take any recommendations you might have for a better evaluation.:grinpimp:
 
I trust the distributor machine more than any human hands even mine, did work like this for 20+ years but dont have the tools anymore they burnt up in the campfire 11/2022.
 
A sensor for the distributor and 8 new LS coils.


Far better than anything else.

I have the MSD box and coils.

My Cad500 never sounded better or produced more power. Wish I hadn't sold that truck.
 
BTW, I also have all this crap I found. I don't have any Cadillac engines anymore:

 
If your determined to use the hei start looking for a sun distributor machine so you can set the advance right via different springs. That could turn into a side bizz as well, its the only way to set dual points precisely afaic.
 
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I've thought about doing a weird LS type injection swap on it... then I remember it is in a POS and not worth "THAT" much money:lmao:

On the Cad parts, I got a steal of a deal on my 472 that was "low end" upgraded everywhere: cam, Edle intake, headers, 368 oil pan, the HEI distrib, and rocker system:
donor5_sml.jpg
 
I've thought about doing a weird LS type injection swap on it... then I remember it is in a POS and not worth "THAT" much money:lmao:

On the Cad parts, I got a steal of a deal on my 472 that was "low end" upgraded everywhere: cam, Edle intake, headers, 368 oil pan, the HEI distrib, and rocker system:
donor5_sml.jpg
A batch fire injection system and coil near plug would make that a killer.

or send me the intake and I can do this and go all LS injection for more power and MPG:

1648938880681.png
 
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Just envious here. Owned two '68 Cads with the 472. Sure would like to get another. Here to watch.
 
Just envious here. Owned two '68 Cads with the 472. Sure would like to get another. Here to watch.
This will be second 472 I've dropped in a Land Cruiser. The other never hit the road but fired up and put a lot of rocking on the chassis:homer:

A batch fire injection system and coil near plug would make that a killer.

or send me the intake and I can do this and go all LS injection for more power and MPG:

1648938880681.png
What is the setup in the picture? Chevy intake with injector bungs welded on along with a carb to throttle body adapter? I do like that adapter:smokin:

I looked at the article you provided and I tried to find the distrib they recommended for a Cady... no such thing:homer:

I got all the TBI stuff cheap and in hand. Without a tune, it won't be perfect. But the rule of thumb I've heard with the old TBI setup was the stock tune will work for ~10% difference in hp/cubes. I want to say under $300 including rebuilding the 2" TBI with new injectors. Harness, two 2" TBIs, distrib, new sensors, etc.

The MPG isn't a huge concern since it will be the plow truck and dumb wheeler... I've only got ~35 miles to get to the Con so even with the ~15 gallon fuel cell, I should be good.
 
Would love to integrate that setup into my 6.0l in my 07 Silverado, might fix its misfire issues that seem to be ongoing no matter what I do.


A sensor for the distributor and 8 new LS coils.


Far better than anything else.

I have the MSD box and coils.

My Cad500 never sounded better or produced more power. Wish I hadn't sold that truck.
 
This will be second 472 I've dropped in a Land Cruiser. The other never hit the road but fired up and put a lot of rocking on the chassis:homer:


What is the setup in the picture? Chevy intake with injector bungs welded on along with a carb to throttle body adapter? I do like that adapter:smokin:

I looked at the article you provided and I tried to find the distrib they recommended for a Cady... no such thing:homer:

I got all the TBI stuff cheap and in hand. Without a tune, it won't be perfect. But the rule of thumb I've heard with the old TBI setup was the stock tune will work for ~10% difference in hp/cubes. I want to say under $300 including rebuilding the 2" TBI with new injectors. Harness, two 2" TBIs, distrib, new sensors, etc.

The MPG isn't a huge concern since it will be the plow truck and dumb wheeler... I've only got ~35 miles to get to the Con so even with the ~15 gallon fuel cell, I should be good.
Not hard to mod the distributor you already have.

Yes, I can mill/weld bungs in and make fuel rails. You can then run whatever intake elbow you like.
 
So I'm getting ready to track down a coil. So far, it sounds like the "performance" brands aren't really worth the upgraded cost. Is it worth the cost of AC Delco(d504A) or is the other budget brands like WVE, NGK or Standard Motor usable?
 
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