![]() Then, once you get that curve, your vac adv will need to be about 12 - 15° ON TOP OF the "total" timing. All of these numbers are with the vac adv disconnected. Most likely, your car will run best with the "total" timing set to about 36°, as described above about 18° of centrifugal retard at low RPMs the mechanical advance curve starting just off idle (NO LATER THAN 1200 RPMs), and "all in" by about 2800 RPMs. With the cam you have, most likely your dist has too much centrifugal advance (the kind that takes it from "static" to "total" timing). what you set by twiddling the distributor, should be set to give this timing, and then the weights & springs should be tuned to provide the curve you want, starting from this point. This is your "reference" timing if you will, the TRUE measure of "what the engine wants". Use a light that flashes EXACTLY when the spark occurs, without allowing it to make some kind of internal "guess" at how far different from that to light. DO NOT use a "dial-back" timing light they are absolutely not dependably accurate at high RPMs. Measure this with the vac adv disconnected and the engine RPM high enough that it no longer advances any farther. Then, given what heads you have, your engine will want somewhere real close to 36° of "total" timing. Then, make additional marks on the damper every 10° BTDC, so you have ACCURATE knowledge of where those points (which would otherwise occur when your new ACCURATE timing mark is off the pointer) REALLY are. If you have not done this, or you did not do it when the engine was built, then YOU DON'T KNOW WHERE TDC REALLY IS, no matter what you think. Find TDC, mark your damper to match your pointer, now you have an ACCURATE reference. In an assembled engine, the easiest way to do that is to put something light and flexible in the #1 plug hole, and turn the engine SLOWLY by some means other than the crank damper bolt, until it just touches the object (as determined by watching for it to move) then turning the engine the opposite way until it touches the object again. Not that the "numbers" really matter but, if you want to know what they are, you must first find #1 TDC ACCURATELY by some means independent of the timing pointer. Given that, it's no wonder you're getting screwy results with "numbers". Most likely, you have an aftermarket timing pointer, and a stock crank damper. ![]() ![]() Give it what it wants, no matter what you think of the "numbers". If the engine wants it, the engine is right. Engines don't read service manuals or timing lights. ![]()
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