Has anyone ever encountered this timing problem? I have a '68 Chevelle SS with a 1974 big block. When rotating the distributor I am unable to bring the timing mark on the pully far enough up to register on the degree tab on the engine. The car idles well (no pinging). Is it possible the cam was installed incorrectly?

last time I had that happen I discovered a bad balancer.
Take out #1 and slowly tap/crank to tdc with finger over hole, then get a breaker bar and slowly rotate crank with a thin probe in the hole. and feel for the piston tdc. I bet the balancer slipped.
Good luck
Milan

First, I'd verify When the piston is at TDC by using a piston stop in the plug hole.When you get the #1 piston up to TDC, see if the mark is lined up with the pointer and the rotor is pointing to the #1 piston......

If the mark is on the pointer but the rotor is not pointing to #1, then dist is installed a tooth or 2 off..

I'm taking it to mean that you can't turn the distributor enough cause it hits the firewall before you can get the mark on the pointer,correct??

You may have the same problem I have.
All last year I was having problems timing mine. The numbers that kept coming up made no sense. Well after having it apart this winter (for a differnt problem )I think I found out why smile.gif .
http://www.chevelles.com/showroom/BLT4FN/Img_0086.jpg
This is the balancer installed with piston at TDC cam NOT connected in any way. Thought the balancer had slipped, so I purchased one and the same thing. Found a marker the same as the one I have and they were the same. :confused:
Nobody could tell me why this was like this so assembled my motor and now use the 4* mark as TDC.