Who Builds A Quality HEI Anymore?
Race Director
Joined: Mar 2017
Posts: 11,931
Likes: 4,497
From: Virginia
DUI #1 failed at 10 miles.
The car ran great, better than it did with the old distributor, until it quit.
Got it towed home, verified no spark, swapped in the old distributor and it fired right up.
That was on a Sat., so on Sun. I was texting with Summit returns, they got a new one shipped out, I think I had it by Tues.
The second one one lasted 120 miles, this time it quit after a 20 mile drive, half a block from home.
I was carrying my spare distributor and tools, so I swapped it out and limped it home (I was too frustrated to mess with the timing, I made it run well enough to limp it half a block).
Summit says two failures is rare, they have very few failures on the DUI distributors.
They suggested I contact DUI. If I get no help there I'll swap the module out and see what it does.
This car ran for 1600 miles with the old distributor while under my ownership.
Two new ones fail?
I have 14.22 V @ idle @ the distributor, 14.17V @ 4000 RPM, both with no load.
New upgraded GM alternator (I forget the amperage, it was sufficient for the electric fans I installed).
I can't think of anything on the car that would cause the module to fail.
The car ran great, better than it did with the old distributor, until it quit.
Got it towed home, verified no spark, swapped in the old distributor and it fired right up.
That was on a Sat., so on Sun. I was texting with Summit returns, they got a new one shipped out, I think I had it by Tues.
The second one one lasted 120 miles, this time it quit after a 20 mile drive, half a block from home.
I was carrying my spare distributor and tools, so I swapped it out and limped it home (I was too frustrated to mess with the timing, I made it run well enough to limp it half a block).
Summit says two failures is rare, they have very few failures on the DUI distributors.
They suggested I contact DUI. If I get no help there I'll swap the module out and see what it does.
This car ran for 1600 miles with the old distributor while under my ownership.
Two new ones fail?
I have 14.22 V @ idle @ the distributor, 14.17V @ 4000 RPM, both with no load.
New upgraded GM alternator (I forget the amperage, it was sufficient for the electric fans I installed).
I can't think of anything on the car that would cause the module to fail.
https://www.corvetteforum.com/forums...on-is-doa.html
If I ever had any intention of installing a distributor again, I'd run a Progression Ignition programmable unit. And keep a proven HEI dist as a spare.
https://www.corvetteforum.com/forums...s-for-sbc.html
Team Owner
Joined: Jun 2001
Posts: 23,367
Likes: 1,061
From: Virginia USA
Not to hijack the thread but I've been looking at Progression Ignition tach drive dizzy. It has an option for $200 for launch control (don't need it) Nitrous retard (don't need it) and data logging - that's what I want. Seem like a lot for just one feature that I'd be using. For those who've got one without data logging can you still see your curve and adjust in real time etc. My Sniper 2 system can capture timing, at least with my current MSD with a Digital 6AL box.
Race Director
Joined: Mar 2017
Posts: 11,931
Likes: 4,497
From: Virginia
Not to hijack the thread but I've been looking at Progression Ignition tach drive dizzy. It has an option for $200 for launch control (don't need it) Nitrous retard (don't need it) and data logging - that's what I want. Seem like a lot for just one feature that I'd be using. For those who've got one without data logging can you still see your curve and adjust in real time etc. My Sniper 2 system can capture timing, at least with my current MSD with a Digital 6AL box.
Melting Slicks
Joined: Apr 2023
Posts: 2,751
Likes: 1,612
From: Poplar Bluff MO
Not to hijack the thread but I've been looking at Progression Ignition tach drive dizzy. It has an option for $200 for launch control (don't need it) Nitrous retard (don't need it) and data logging - that's what I want. Seem like a lot for just one feature that I'd be using. For those who've got one without data logging can you still see your curve and adjust in real time etc. My Sniper 2 system can capture timing, at least with my current MSD with a Digital 6AL box.
JT
Drifting
Joined: Jun 2025
Posts: 1,685
Likes: 588
a better heat sink for HEI Ign Control Module in C3
If the old one hadn't run for so long I'd suspect something on the car was causing the failure.
I'll see what they say tomorrow but I'd like to reinstall the DUI and, if it's still dead, swap the module from the old one that runs.
I wonder if it's heat related, we set records for high temps here today.
Last week I was out for a much longer drive but it was a cooler.
I'll see what they say tomorrow but I'd like to reinstall the DUI and, if it's still dead, swap the module from the old one that runs.
I wonder if it's heat related, we set records for high temps here today.
Last week I was out for a much longer drive but it was a cooler.
Without that HTP, any module will overheat and subsequently fail.
Trucks with L31, L30 iron head Vortec motors were final GM V8 to use a distributor; and they are also a revision of HEI (but certainly not 4-pin).
Those have their Ign Control Module mounted remotely; attached to a finned aluminum heat sink that's mounted to a bracket atop intake manifold.
That finned heat sink can be retrofitted to any GM vehicle with a V8. Find em at junkyard or new at RockAuto etc.
Regardless, Module still REQUIRES heat transfer paste.
https://www.rockauto.com/en/moreinfo...=11323&jsn=534
Thread Starter
Pro
Joined: Apr 2010
Posts: 600
Likes: 249
From: Carson Valley
DUI directed me to test the reluctor and coil, if they were good (they were) I could swap the module from my good distributor to theirs (I did) without voiding the warranty, then call them with the results.
Car runs w. their distributor and the old module, they're sending me a new module and a set of springs. I mentioned the timing is all in by 2000, I'd like to move it out closer to 3000 per Lars timing instructions.
Interestingly enough, the first one I had was perfect in that regard.
Car runs w. their distributor and the old module, they're sending me a new module and a set of springs. I mentioned the timing is all in by 2000, I'd like to move it out closer to 3000 per Lars timing instructions.
Interestingly enough, the first one I had was perfect in that regard.
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Drifting
Joined: Oct 2005
Posts: 1,916
Likes: 48
From: Angier nc
I have the Firecore hei in my 454 and one of their billet distributors in my BB stroked Mopar as well. No problems to date.
https://firecoreperformance.com/part...rs/chevy-dist/
https://firecoreperformance.com/part...rs/chevy-dist/
Drifting
Joined: Jun 2025
Posts: 1,685
Likes: 588
I have the Firecore hei in my 454 and one of their billet distributors in my BB stroked Mopar as well. No problems to date.
https://firecoreperformance.com/part...rs/chevy-dist/
https://firecoreperformance.com/part...rs/chevy-dist/
Country of Origin ?
Thread Starter
Pro
Joined: Apr 2010
Posts: 600
Likes: 249
From: Carson Valley
Module #3 (#2 in this distributor) lasted 9 miles, I had the old module with me to get home on.
They have got to find a better supplier.
They have got to find a better supplier.
Last edited by AKjeff; May 19, 2026 at 09:03 PM.
Race Director
Joined: Nov 2006
Posts: 13,193
Likes: 7,793
From: Sunshine Coast, Queensland, Australia
2025 C3 of the Year Finalist - Modified
2024 C3 of the Year Finalist- Modified
2022 C3 of the Year Finalist - Modified
Cruise-In VIII Veteran
They are made in Tennessee. Last I heard that is still part of the USA.
But perhaps they purchase some component parts?
That I do not know.
What I do know is I dropped one into my engine a few years back and it's been flawless.
I have judged at Corvette shows several times and seen an awful lot of them installed. And everyone loves them.
I'd like to believe that the OP of this thread is definitely the exception, not the rule.
But perhaps they purchase some component parts?
That I do not know.
What I do know is I dropped one into my engine a few years back and it's been flawless.
I have judged at Corvette shows several times and seen an awful lot of them installed. And everyone loves them.
I'd like to believe that the OP of this thread is definitely the exception, not the rule.
Race Director
Joined: Mar 2017
Posts: 11,931
Likes: 4,497
From: Virginia
ACDelco GM Original Equipment 93440806 Ignition Distributor. Nearly $600- from Amazon! And it still needs endplay shims, springs, and a different vacuum can. But it works!
I've paid less for complete, running LS engines.
Thread Starter
Pro
Joined: Apr 2010
Posts: 600
Likes: 249
From: Carson Valley
Advanced
Joined: Aug 2025
Posts: 80
Likes: 44
I only ask because, I bought a new digital one from Harbor Freight and when I first rev the throttle the timing mark jumps around some. I jump the gun and pulled my distributor out thinking it had a problem. Nothing. I have a new dampener too. Finally pulled out my old school timing light and it showed a non jumping timing mark when first touching the throttle. IDK why but just guessing the new digital one takes a second to do its thing. Now that I realize that I do really like the digital one. It's probably just a cheapo Harbor Freight thing. It can make you think there's issues though.
Last edited by LT-1 1970; May 24, 2026 at 09:52 AM.
