pinging noise on acceleration

[bitbyter]

We took off today trying to get to a family reunion type camping trip, but my rig was over heating some and pinging like mad going up the hills.   I got the overheating problem fixed, but she is still pinging really bad.   From everything i can find it's the timing being to retarded, so i went out in the country here where i could mess around with it.  I think I've had the distributor in every spot it will still run in....lol  not really getting much of a change.  I disconnected the vacuum advance just for giggles and actually seems to have gotten a little better.  Also could it just be lower octane gas or a lean mixture?  Oh yea forgot to mention it's a 76 chieftain with a 440  any help would love to get into the woods before the weekend it gone...

thanks

[Oz]

You can cross octane rating off the list.  These motors don't need anything more than 87. 

[bitbyter]

dang

[LJ-TJ]

Well my guess would be get your timing set with a timing light and have your fuel/air mixture adjusted.

[Oz]

When you set your timing with a light.  Watch the mark you put on your harmonic balancer.  If it jumps all over the place instead of hitting the same place every time, it could be slipping and this makes it impossible to set your timing correctly.