Ric,
>I am using and Aldon Rally (I think) distributor. It appears to have
>about 20 degrees of mechanical advance coming in by about 3500 RPM.
>
>I am trying to figure out where it needs to be for best power.
>
>Currently I have it set so at 1000 rpm it is at about 5 degrees BTDC.
The stock centrifugal-only Lucas in 67 1275s is set to 22° @ 1200 rpm and
the centrifugal advance increases the advance from there. I used to have
the Robert Bently book that gave total advance for the different
distributors, but sadly I've lost it somewhere. I suspect the total
advance with the stock Lucas distributor is supposed to be much higher than
the 5 + 20 = 25° total advance you are stating you have.
If I was going to approach this problem myself, I would find out the
centrifugal advance for the stock centrif-only Lucas and add this to the
22° base and subtract a few degrees (for the timing spec being at an rpm
where the centrifugal advance has already started to work). Then adjust
the aftermarket distributor to this number (at an rpm where the advance is
maxed). That should get it in the ball park as long as the advance curve
is proper. It's trial and error after that.
That's what I hate about aftermarket distributors. You'll never know for
sure.
Good luck,
Les
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