I'm confused. I have just installed a new cam in my 350 chevy motor and I want to make sure I have it right before I close it up. My timing marks are lined up like they should be, but when I turn the motor over the intake valve opens first. When it closes the mark on the cam gear is at the top and the mark on the crank gear is at the top. One more turn of the engine and the exaust valve opens and closes and the marks are lined up again. The question is, should the marks line up on the exaust stroke or the intake stroke. I want to make sure that I set the distributor in correctly the first time, so should I put #1 firing when the marks are lined up or when both marks are at the top. I know this sounds like it is comming from a beginner, so be gentle.