[Cliff R]

Here's part of an email to Adam, but it fits well here since we've pretty much turned this into a tuning thread:

"The order of tuning goes like this.

First find total timing, drag strip, dyno, seat of the pants, etc, without detonation.

Then find the initial timing the engine likes the best. If it likes 36 total and 16 initial, then a 20 degree mechanical curve is required. If it likes 36 total with 12 initial, then a 24 degree curve will be required, etc.

Tune the idle mixture screws with each test of initial timing to find out where they need to be, and make sure to do some fully heat soaked cranking tests to make sure it’s not “bucking” the starter.

Next add in vacuum timing (I use and prefer ported for most set-ups) and do some light throttle cruising and fine tuning the APT if/as needed for best results.

This part of the testing may take several tanks of fuel once you get close, but you can nail down the very best performance and fuel economy with this part of the testing.

At this point you have a choice as to add it initial timing via the VA with manifold vacuum for more timing at idle. This may help with some set-ups, typically those with not enough compression for the cam choice (low vacuum at idle), but is seldom if ever needed on an engine with a well chosen CID/compression/cam combo."

The reason we find total timing first, is that we do NOT want to damage the engine moving the distributor around trying to find initial timing. Detonation will destroy the best prepared shortblock, so we want to find the ideal total timing at full load before we start tuning the mechanical and VA.

The only part of tuning that leaves us with is how quickly the timing curve comes in and at what rpm it reaches full advance. Most engines don't want or need ALL the timing in right off idle, but to this day I continue to see folks installing "kits" that get total timing in really early. In almost all cases, the curves as so quick and springs so light that some of the timing is actually in at idle speed, which makes idle tuning difficult, if not near impossible, and for auto trans cars this causes a HUGE drop in engine rpms when the trans is placed in gear (sound familiar?).........Cliff