New to me MSD 6A box. What is realistic spark plug gap?

Do what he said, and then post a video so all can see. It's amazing. Spark will not be your problem if you're running rough.

 

Lets assume your comment is correct then as the gap increases the power needed to spark the given gap must increase. Meaning more gap equals more voltage delievered. Increased gap will be govern by the ignition systems ability. MSD is some serious stuff, even they recommend opening the gap at .005 increments to get the largest possible gap

 

OK, weather blew through and streets were dry today, and the MSD box set at .060 runs FINE!!!

It even got rid of that last little bit of burble at low speeds.

 

I am still curious why you need the Pertronics AND the MSD6 box. I thought the MSD 6 would use the points as a switch with no current thus the points lasted pretty much forever?
Clint

 

I had the pertronix since years ago. Just got the MSD and with no wearing parts on the pertronix, I am keeping it in there.

 

the rub block on the points wears out causing the timing to change. this requires ocasional maintance and eventual replacement. i would recomend geting a duraspark dist. to go with a msd box. they use the same type of trigering method. the duraspark dist. has wider post spacing that will help prevent crossfireing at higher rpms.

 

You can get a replacement cap and rotor that converts the old distributor into a large-cap version. As mentioned, highly recommended with a high voltage system.

 

I have the Pertronix installed on the stock 302 distributor. A new one from O'reilly, since the original one rusted solid and the advance wouldn't work.

Then put in pertronix, and then put on a spacer that makes the top bigger, and then a 5.0 big top with the tips sticking up that look like spark plugs. I guess they call them HEI?

I also swapped out the dizzy gear to steel to match the roller cam.

Then added the MSD.

 

That makes since. I didn't think about the rub block wearing down.
I used a Dura-spark for a while with mine then went to an MSD and couldn't tell a bit of difference. It was a lot easier to tune the advances but that is all. Looked nice
Clint

 

I had a penotrix catch on fire and burn inside the dist and melt the cap and rotor. Called tech line said it was because of a 7al-2 i had on the car. Maybe they have fixed the issue by now. This has been 10 years ago or so. May not hurt to carry some poimts with you. i think the duraspark dist will be more reliable in the long run. The msd dist uses the same guts. 85 mustang will have the steel gear for the roller cam.

 

I actually carry the points in the tool box. I have heard a couple of stories like yours, so I keep them handy just in case.