[69gmcc10]

The weather has been intermittently good here, intermittent as in it snowed Monday, rained Wed snowed again yesterday, it’s now overcast and 53, and tomorrow should be 70.

Random misfire problem fixed! All it took was new wires and a new cap, but my timing curve was less than desirable initial was 17-18* and my total mechanical was 30*. That total timing is not unreasonable for a vortec engine, but having that much timing initially was causing predestination and a stumble off idle. So, to the trusty inter-web I went and found that forum member HEI451 who happened to be brilliant at hei units, so brilliant he modifies and sells them, recommends the base plate stamped 375 and weights stamped 41 to get 21-22* of advance. I could have ground the HEI unit’s base plate notches larger, but you can also change the total advance of an HEI like GM designed it do by using different weights, so yesterday I skipped lunch and spent it in a junk yard wearing a suit and tearing HEI units apart to find the mythical 41 weights, I already had a 375 plate.

**The numbers on the center plates signify they are shaped differently to allow more or less mechanical advance in a unit in correlation with the shape, size and weight of the weighs. If you start mixing and matching plates and weight you can find allot of different amounts of advances and curves.**

The picture is of the 139 weights and the 41, the 41s are on the outside, and other than weight and height there is not much difference in shape. The attachment is a chart I found of just a few weight and center plate (CP) combinations and the advance results they produce. You can also see what happens when you pace the center plate face up or down. (These are the results of some dude doing his own experiments and I can not vouch for there accuracy, but they do provide food for thought.)