CRG Discussion Forum

Camaro Research Group Discussion => Mild Modifications => Topic started by: dtep on January 13, 2025, 12:04:08 AM

Title: Big Cap HEI Distributor in Small Block 68 Camaro
Post by: dtep on January 13, 2025, 12:04:08 AM
Has anyone successfully used a "big cap" HEI distributor in a small block 68 Camaro without modifying the firewall?  If so, what brand and model did you use?  Did a 14 inch air cleaner fit without modifications?  The car I am rebuilding came with a small cap HEI distributor and one of those big honkin' yellow Accel coils mounted on the firewall.  I'm looking for something more subtle and would prefer not to have the coil visible at all.  TIA.
Title: Re: Big Cap HEI Distributor in Small Block 68 Camaro
Post by: JST69Z28 on January 14, 2025, 08:53:24 PM
I recently installed a Summit Ready to Run vacuum advance small cap distributor in my 69 Z28 because the large cap HEI didn't fit, and I didn't want to bend the firewall.  Even with that the 2 front spark plug wires (8.5 mm) were a tight fit with the air cleaner on but still worked.  I ordered their coil, (also had a big one previously) not too big and works great.  Photo attached.
Title: Re: Big Cap HEI Distributor in Small Block 68 Camaro
Post by: sdkar on February 06, 2025, 06:45:12 PM
I have...but had to customize the firewall.  I've seen some guys beat the firewall in and though it works, it looks bad.  What I did was make a cutout to allow for room for the larger HEI.  I then made a flanged box out of sheetmetal and riveted in over the hole with sealer.  It worked fine. 

Now, if you simply want HEI, you can convert your the small distributor already in your car.  It's super easy and not all that expensive to do.  I did this to my 69 Camaro and noticed an improvement for sure.  Easier starting and more responsive throttle. 

I used Crane Cams XR-i Points to Electronic Ignition module.  You will have to upgrade the coil as well, and they make one that looks exactly like the factory round one and will fit in the existing coil bracket.  I did this over 20 years ago, and it still runs great.  One of the best upgrades I could recommend. 

Here it is at Summitracing -
https://www.summitracing.com/parts/fst-750-1715
Title: Re: Big Cap HEI Distributor in Small Block 68 Camaro
Post by: boomer632 on February 06, 2025, 06:57:44 PM
Maybe take a look at Progression Ignition. Electronic ignition distributor, reliable spark up past 10K RPM. And the bonus is it looks pretty stock as a small cap would, no firewall mod, uses stock looking coil and you can adjust your timing on the fly from the drivers seat through the BT app on your phone. You can also make custom timing curves based on what driving you are doing. I have one installed on my 69 L78 motor. Im a purist, and prefer stock over modified or resto, but the benefits outweighed just about everything compared to a points system.
Title: Re: Big Cap HEI Distributor in Small Block 68 Camaro
Post by: KurtS on February 08, 2025, 03:12:36 AM
I was looking at Lectric Limited's conversion kit: https://www.lectriclimited.com/product/breakerless-se-electronic-ignition-conversion-7/
The Crane set-up looks interesting.


I've seen an HEI squeezed in there, but I think how much room depends on the engine mounts.
Title: Re: Big Cap HEI Distributor in Small Block 68 Camaro
Post by: Sauron327 on February 08, 2025, 03:15:14 PM
I was looking at Lectric Limited's conversion kit: https://www.lectriclimited.com/product/breakerless-se-electronic-ignition-conversion-7/
The Crane set-up looks interesting.


I've seen an HEI squeezed in there, but I think how much room depends on the engine mounts.
I put that on a customer's car and the builder ran it on the dyno. Generally he uses Crane. I'd use Breakerless if and when I get rid of the points distributor I've been running for over 75K miles. It's only one wire so it appears more stock for those who prefer it, which does not concern me.
Title: Re: Big Cap HEI Distributor in Small Block 68 Camaro
Post by: David K on February 08, 2025, 05:55:09 PM
The limited space from the big HEI cap the the firewall can vary due to the engine mounts. The modern systems eleimate that possible issue, but if you had one to test fit I'd say go for it.