I took my 69 out for a ride today and all was well until it cut out. I tried a dozen times to start it and all I would get is back firing through carb and exhaust. I towed the car home and pulled a plug wire to check for spark. If I let the car sit for a minute then try I get 1 or 2 sparks then nothing.
I have an MSD 6AL box with an MSD HVC coil and pro billet dist. All is about a year old with maybe 50 miles total on the entire car...probably less. I checked the voltage at the coil + and - and I get nothing. I tried jumping 12 volts to the - on the coil and I get a big spark and the wire gets hot quick.

What to try next?

Thanks in advance,
Phil

Pull the dist cap, I had the same problem, found the middle button on my dist cap has shattered into a million pieces. What happened was moisture got inside (nonvented old style cap) and when I ran it 10 miles down the freeway it broke up and destroyed the button that goes from the cap to the rotor. New caps have a vent to help prevent such an issue.

12v to the (-) side was not a good test. You may find you did damage to the ignition box. Pulling the cap is a good first bet. I've seen a couple other issues with breaker point setups that behaved the way yours is. First was coil overheat by not running a ballast resistor. But you'll have to interpret that advice against your ignition box wiring requirements. Another is an improperly greased distributor that slung a wad of grease on the breaker points.

check the paperwork you got with the MSD unit, it has troubleshooting info. Also check their website. Jumping it like you did may have fried the MSD box. Is your distributor a points type or mag trigger?

I have the pro-billet part# 85551...I believe it is mag type. I ordered a new cap and rotor since I had just washed off the engine not long before it cut out. I hope I didn't fry the 6AL since it is neatly under my dash...didn't want to see it again for a long time!

... since I had just washed off the engine not long before it cut out ...

Be prepaired to see that again. Distributor caps often get wet inside after a wash or even after a cold snap where moist air condenses inside the cap. The old mechanics trick for this is to remove the cap, wipe the cap, rotor and other parts and spray some WD-40 in there. Works like a champ. If the rotor and cap aren't corroded or burned, you probably don't need to replace them.

I tore into it today and the cap was definately shot. The button part in the center of the cap was cooked off. I put on a new cap and rotor and still no go. I tried the msd tests for the 6al and they all failed. It is either the 6al or coil. I am going to try and dig up a spare coil but I am guessing the 6al is toast.

What do you think might have mauled the distributor? Is it hitting against the firewall or perhaps the cap wasn't on completely?

Hi to all
I am having a similar problem to pwoolford.
I am getting a nasty backfire on hard accelloration. I have fitted a new custom curved distributor and plugs. I have not replaced the ignition leads as the resistance check is good. I am beginning to suspect a valve problem. Any takers for this one.
Thanks to all
Tom Mangan
Ireland.

Well I can't even believe what I just found but here goes....man this is a good one!!

I replaced the 6AL and still no go. I tried the MSD troubleshooting steps of shorting the trigger wires and I did get a spark at the coil this time. I called MSD and they said it is probably the distributor. They told me to test the ohms at the dist. I pulled the dist to take it to work where I have the meter and it tested ok. So I get ready to put the dist back in the car and notice the gear is destroyed on the dist!!

http://www.philwoolford.com/camaro/hell1.jpg http://www.philwoolford.com/camaro/hell2.jpg
http://www.philwoolford.com/camaro/hell3.jpg

I'm not sure how much more of this I can deal with. I have about 70 miles on this motor and since it first started 2 years ago I have already pulled it due to wiped cam. I also had oil leaks that I couldn't fix so I gave up and put the car in the shop because the rear main was leaking so they jacked it up and replaced the rear main seal.

I can't imagine what tore this dist gear up but I am sure I better pull the motor to check the bearings anyway. Any ideas what could chew up a dist like this? Anyone want to buy a 350 SBC CHEAP!!!

The gear probably ate its self because the cam gear is a harder metal than the distributor gear. Check with the Cam maker see if there are any special requirements. Sometimes you need to change the distributor gear out for one made with stronger metal.

After much pain and stress I ripped out the entire MSD system and bought a proform HEI distributor. Dropped it in and it fired right up. I suppose I'll change the oil and cross my fingers that the filter caught all of the gear parts.

Thanks for all of the help!