Big distributor cap for Delco on a 258?

I just picked up a an older MSD 6A and wanted to use it with my stock (72) Delco distributor and points. The old cap, rotor may need to be changed. Does anyone know if an adapter and big cap is available for the Delco 6? I see a lot of info for 8's but haven't found these for the 6. Also, are there any good (cheap) sources for 8.5mm wiring?

Thanks

 

No reason you can't use an MSD 6a with a 6 cylinder motor. For wiring look on MSD's web site you can download the instructions and wiring diagram. Why do you want to go with a larger cap? No reason unless it's built for high end high rpm drag racing.....

 

That little peanut cap of the old delcos have a propensity to crossfire as the terminals are so close together. If you want to up the spark voltage it can get even worse.

You should just pop for the Duraspark distributor out of the '79 CJ. It uses the big Ford two piece cap.
It's the prefered way to incorporate the MSD ignitor.

It's known as the "Team Rush" upgrade.
Pretty thorough write-up here...
http://www.jeepforum.com/forum/f8/i-6-teamrush-upgrade-definitive-669495/

I just did the distibutor retrofit but used my stock coil and the difference over the point system way truly amazing

 

That looks nice Drednot!
I do hope you plan on carrying an extra ignition module with you. I'm not a fan of that conversion because of the duraspark module. When it's manufactured the printed circuit is folded in half and installed in the box. As you can imagine over time and vibration the printed circuits break at the fold. As they heat up they then break contact but when they cool down they make contact again. Drives you nuts trying to figure it out. If I were going for the larger cap I'd use a 6 cylinder gm hei and change the drive gear. It cleans up the engine bay, parts are everywhere, and aren't so problematic with high miles. I'd still carry an extra module, but they take up much less space.
Back when I worked for Ford we saw a silly amount of failures of both tfi parts and duraspark modules

 

I don't know of any big cap for the Delco 6-cylinder distributor. I presume you're thinking of something like the MSD Adapta cap for V8s.

I'd swap in the Duraspark distributor and run the TFI parts. If you don't like the Duraspark module, substitute a HEI module - either module will work with either distributor, after you change the connections. IMO putting the coil under the cap is a bad idea, and the TFI'd Duraspark will avoid that. AFAIK the factory Ford/Motorcraft/AMC Duraspark modules were fine - my J20 is still running its original module. I expect you get what you pay for with replacement modules - and there are some very cheap modules out there.

You can also use the HEI distributor from a 250cid Blazer, which has the coil outside the cap.

 

Yes, I was looking for something like the Adapta- Cap but for the 6. The reason I was looking for this was to prevent cross fire and other issues related to the hotter spark from the MSD. I'm trying to keep it simple and was hoping to not need a new distributor and TFI box.

From what nickmil say's it appears that I can run the stock cap and wires without fireworks. I guess I could try it. I'm told that I could also minimize crossfire etc. by keeping the plug gap at the low end of the recommended .050-.060 gap. I'm not going to be running this engine at high revs and was just hoping to get a bit more efficiency with minimum components.

Anyone beside nickmil run the stock distributor and wires with a MSD box?

 

I don't run an msd with an inline 6 but have run it with lots of v-6's and v-8s with the small points caps with no issues until high rpm. I'd try it and if you have issues you can easily disconnect it or swap distributors later. I'm still not and never will be a fan of duraspark and tfi components for the reasons I've stated. I've just replaced too many of those components compare to most other systems




The coil in cap works fine as long as quality cap and rotor are used. Problems arise when substandard parts are used or are misinstalled. Another option is gm used an inline 6 distributor with an external coil.

 

Sorry, I went way off track here.

If you have the MSD 6A and want to convert to a big-cap distributor, you don't need an additional ignition module. The MSD will trigger off either a Kettering trigger (points) or a variable reluctance (VR) trigger. The easiest way to get a VR trigger is to use a Duraspark distributor, and send the VR signal from that directly to the MSD module. A HEI distributor of any flavor will contain a module, which theoretically you could remove and discard... but the Duraspark seems more sensible. MSD has some pre-made cables that make using the Duraspark distributor simple.

You don't need a hotter coil with the MSD CD module either... so all you'd need is the Duraspark distributor, the TFI cap/base/rotor, and HEI-style wires.

So you could go with the bigger cap with a distributor swap.

I'm using the Summit in-house universal wire set on both my V8s. You should be able to find a universal set for whichever type distributor you use. Or, you could look on RockAuto for a set to fit your application. If you keep the Delco distributor, you can buy a good set of silicone wires for about $20.

 

Thanks all. Good info. So Tim, is there a preferred donor year/model for a plug in Duraspark distributor? The Duraspark minus the module should be a good way to go if the Delco goes up in a blue flash. The possibility of some improved performance/efficiency for the low bucks (them MSD cost $20 on Craigslist) is pretty cool. I might even get lucky and find a Duraspark distributor on Craigslist.

 

I've heard that the '78-79 distributor has a better advance curve. I expect you can fiddle with any year and adjust it to your needs. ALl the Duraspark vacuum advances are adjustable, AFAIK. Here are some instructions about advance curve tuning from JeepForum: http://www.jeepforum.com/forum/f8/ask-jeephammer-anything-thread-674001/

 

Thanks. I think I have what I need to be dangerous.