Another 350 tuning thread

[rspears]

First, welcome to CHR from another gearhead engineer! I agree with Dave, it sounds like you might not have had #1 at TDC Compression Stroke when you stabbed the distributor. Another thing that I ran into was that my distributor wasn't seated all the way in the manifold bore when I set my base timing, and then when I tightened the hold down it pulled it down tight and retarded my timing 12*, but it sounds like you've checked yours after it's all tight. Are you using a quality dial back type digital timing light, or are you reading the damper marks at the pointer?

Another possibility is that your damper may have de-laminated from the core and slipped, throwing your "0" mark off; and there have been cases where someone has mis-installed the pointer when doing maintenance on the front end of the engine. You can verify your timing marks in a non-invasive way with some light oil, clear tubing and an old spark plug.
1) Break up an old spark plug and hot glue a length of clear plastic tubing to it (make it airtight).
2) Remove all the spark plugs.
3) Stick your thumb over the #1 cylinder spark plug hole. Rotate the engine using a breaker bar on the dampener bolt until you feel air pressure on your thumb for the compression stroke.
4) Screw in the spark plug with plastic tubing attached and insert the other end of the tube into a jar of light oil. Continue rotating the engine. Bubbles will appear until the piston reaches the top of its travel. When it starts down on the next stroke, the bubbles will stop and oil will begin traveling up the tube. Stop at a convenient point (don't go too far) and mark the liquid level in the tube and also mark the crank pulley at your pointer.
5) Rotate the engine backwards and watch the oil recede into the jar. Continue rotating. As the piston continues past TDC and downward it will again suck oil into the tube. Rotate the engine till the oil again reaches the mark on the tube. Stop at that point and mark the dampener where it lines up with the pointer. You should now have two marks on the crankshaft pulley, and the exact midpoint of these two marks lined up with the pointer is TDC. If you want you can iterate to smaller and smaller separation on the marks by re-marking your tube at lower levels and repeating the process.

If everything checks out you might suspect the new HEI distributor. There are a bunch of guys on here who wouldn't buy a hammer with the ACCEL brand. They seem to spend all of their money on advertising as opposed to quality design and control. Hope you'll post back what you find.