Jonny Miner wrote:
> 
> According to Muir, my type I 1966 engine (the ID # starts with an F) should be
> timed to 7.5 degrees BTDC. The problem is, in the table that shows where each
> year is to be timed, it shows mine as having three timing marks (TDC, 7.5BTDC,
> 10BTDC) but my pulley only has two marks. What do these stand for? TDC and
> 7.5BTDC? Which one should I time to?
> 
> Thanks,
> 
> --Jonny

It has always been my experience that in these modern times the timing 
marks don't mean much.  As usual - gas quality, compression ratio (if 
engine has been rebuilt) type of distributer, altitude, etc. - All 
effect how far one can safetly advance the timing.  My tried and true 
method is to set it @ TDC with a static light so she'll run and after 
making sure all other tune up items (carb, points etc.) are 100%, then 
do the pull test.  With engine fully warm find a good hill and run her 
hard up it full throttle and listen for the ping. Carefully advance the 
timing until you hear the ping then retard it just a tad. Bingo - set.  
Carry a 10 mm around with you so you can make the test enroute a few 
times. Be sure you have it right before a long trip fully loaded on a 
hot day.  Big packed loads are nice - sometimes you can't hear the 
engine but this is bad if its pinging.  Pinging will kill the motor in 
no time so listen for it. good luck.