NOOB with a TIMING light gun

mguner said

Really? 18-20 initial on a stock 440? And it starts hot without hitting against the starter? Several people did mention a range of 34-36. I don't see where anyone said to "set" timing with the vacuum hooked up but to "check" it or see what it is just to make sure you don't melt it down at cruise. If with the vacuum connected and at 3000 RPM you get more than say 45 degrees there is potential for overheating or detonation when accelerating from cruise. Depending on which vacuum can your distributor is equipped with there can be easy or not so easy ways to limit the vacuum advance. Depending on how weak the springs are that hold the advance weights initial can be all over the place.

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Yes. Really. Stock engines can deal with high initial timing because they have low cylinder pressure. That's why engines with high static compression need less initial timing.

It's perfectly normal to have total timing including vacuum in the 60* range at part throttle. Vacuum cans typically pull in around 20* or so.

Perfect example. My stone stock 351M Ford has 21* initial timing at idle. Starts just fine when hot. Has total initial + mechanical of 34*, PLUS whatever the vacuum can pulls in. Runs like a top. Lower compression engines NEED more timing.

Everyone seems to think high initial timing is a "hot rod motor" thing. It's not. A real hot rod motor with higher static compression needs less initial timing since it has higher static compression and higher cylinder pressure.