I have a 73 Camaro, 350. Put a comp cam in it. Put a new MSD Ready to Run Distributor in it but for some reason it won't line up with the #1 piston. The engine timing is set at 12 Degrees because that is what it best runs at. But I don't know what the problem is. I try lining up the rotor to the number one terminal on the cap but for some reason it is always a little off. It will start and run like everything is fine but then after about 20 seconds it will start popping and backfiring. Any help would be greatly appreciated.

If you are trying to set your timing when you put in your distributor, it will never be dead on with #1. If you set the engine at TDC or 0 then, your rotor should point to # 1. Try setting it at 0 and then turn distributor by hand as you crank engine over. Once its running put a timing light on it and set your timing at 12*.

The rotor doesn't have to line up precisely with the lug on the cap. I assume that is what you are getting at. The rotor turns clockwise viewed from above, and as soon as it sees enough of the lug to jump spark, it fires.

You have something else going on causing the belchinfartin and carrying on, and you need to tell us some more about what you have done and symptoms. Then we can help you.

Start by telling us if youare checking your timing with the vaccuum advance unplugged from the vac adv can. And if you adjusted the valves after putting the cam, and if so how you went about it.

bet ya wiped a lobe...timing wont solve that...how did you break the cam in???todays oils arent cam break-in friendly, and there are alot of failures due to that...the tree hugging dirt worshipors made big oil reformulate from the good stuff...there is no more zinc in the oils because it destroys catalytic converters...the motor companys dont want the warranty claims, so they run synthetics and reform oil...the only good for your cam stuff on the market are racing oils now...sorry for the rant...lol...the rotor leads the wire tower by aprox 12 deg to get the 12 deg advance or 12 deg btdc...thats why it doesnt line up...do a cancel test to determine the dead slug...to do this, with engine off, pull each plug wire off completely, and then push back onto the plug, but not locked onto the plug...just so the metal in the wire touches the top of the plug...then start the engine, and at idle, pull each individual wire 1 at a time...pull 1 and listen for the difference in the motor...a firing cyl will go dead, and the engine will run rougher...when you hit the bad 1, the popping will stop, but the idle wont change...let us know what you come up with...

I did adjust the valves the way it says in the book. Tighten all the way down til there is no movement then back off a 1/2 turn. I adjusted the timing with the advance hooked up. I just started and I don't know too much so whatever else you need to know just ask. Its not much of a backfire but it does sound like a clank and pop. But more metal than a boom. I will try doing the cancel test. Thank you. Any more info would be great.

Do you have hydraulic lifters? Hydraulics you tighten 1/2 turn more after the pushrod contacts. NOT loosen. Did you set the engine at TDC for each cylinder to set valves?

Yes, I have hydraulic lifters. So that may be something. And yes, each cylinder was at TDC when adjusted.

Let's define "tighten all the way down"?

That sounds scary... I think your rocker nuts are way too tight. When the lifters are bled down she starts, but as soon as the lifters pump up, the valves aren't closing and she starts popping, then quits.

When you're adjusting the valves, you have to make sure the cam is on the base circle (valve would be closed) then, while wiggling the pushrod up and down, tighten the bolt until it JUST barley won't move UP & DOWN anymore. Then tighten another half turn.

If you haven't done this a lot, easiest way is to adjust the intake when you can see the exhaust for that cylinder is all the way open, and adj. the exhaust when the intake is all the way open.