Thread: My old 390 Tbird will only run at 45 btdc???

Tweet

I question the method/accuracy of determining tdc more than cam timing---also if its a point dist what the dwell is set at---

With #5 being the next cyl in the firing order and questional accuracy of dwell, timing marks/tdc ----

I wrote this article on another forum for small block Chevies, but the procedure is applicable to any motor. If you used a dial indicator stem through the spark plug hole, that's where your problem began. But I still don't understand the 150 psi with 5 inches of mercury. It seems that if the cam was off enough to allow only 5 inches, it wouldn't make that kind of cylinder pressure when cranking.
http://www.crankshaftcoalition.com/w...op_dead_center