i bought a 69 D100 with a slant 6 about 3 weeks ago, 11,550 miles on it documented to be original and the truck reflects the milage shown. I have put a couple hundred miles on it and it ran ok but spark knocked and didnt seem to have a whole lot of power along with a bit of a occasion miss at idle. So I changed the oil, spark plugs, checked the point gap and then thought I should throw the timing light onto it, oddly the distributor slot was at the extent of it's travel which concerned me also. The timing turned out to be 38deg advanced which meant the distributor had to be a tooth out. I set the timing marks to put the engine at TDC and sure enough the rotor was off by a tooth to where it should be. I set the timing to 5 deg btc and took it for a ride it was a day and night difference to what it was before. The temperature gauge stayed at the middle of normal compared to being at the high side of normal. I have concerns that the engine was running hotter than normal and may have caused some damage although if it has it would be minimal. Also I wonder why the distributor was out by a tooth, my thought is that someone removed it to possibly change the points and didn't get it back in right. Any thoughts on this situation and should I be concerned? It does seem to run encellent now.

_________________
After the game is over the King and the Pawn end up in the same box!

My advice is, now that you have it running right enjoy and drive it till it quits. Slant sixes are pretty tough in the overheat department, but I don't know if the overadvanced timing was causing detonation which hammered your pistons/rings/bearings.

If it continues to run good and doesn't smoke like a freight train or blow oil, you should be good.

_________________
82 D150-225/727
02 Dakota-3.9/5 speed
87 GMC C7000-8.2 Detroit Diesel/5+2