if you think you may be 180 degress off, or if anyone does work on their engine and think it may be 180 off, theres a simple way to correct this, and you don't have to crank over the engine. All you simple do is pull the distributor turn it pointing the opposite direction it was pointing, to confirm this the shaft will only go in all the way when the oil pump shaft engages the distributor. So when you turn the distributor 180 degrees(facing the opposite direction) it will engage the oil pump shaft and be at the correct point for TDC, once it spins around. This is only if its 180 off, no need to turn the engine over and find TDC.