Timing

The slant six has two adjustment bolts. There is the one you can see going into the block on top and there is another under the distributor. You can feel it with your hand under the distributor body at about the 10 or 11 o'clock position. It is upside down and screws into the distributor base. My guess is, it's been adjusted some to take up for slack in the chain over the years like Del said in post #9 and you're going to have to adjust it back. I would make sure everything else is in adjustment first such as the points. They should be 40-45 degrees on a dwell meter. Get those correct first and then correct the timing. Normally, getting both the top and bottom bolts in the middle of each of their slots is a good starting point.