No way dude! if you get it wrong try again!! when you finally get it the feeling of satisfaction will be immense!! When I finished my first 911 engine tranny R&R I figured if I ever got layed off I could just go get a job as a Porsche mechanic!! : - ))

Take a couple of days off, organize and clean your tools, straighten up the garage and cut NO corners this time through. I remember the first time I did a cam in a 70s Z car, I had no idea that it mattered what orientation the cam went in!!! ( thank god for non interference motors..)

I bet our wife (and family) is sick about the angst this is causing you. Get a grip relax and enjoy the challenge. You have done the hard part!!

Is it even possible to damage the valves if you turn the engine by hand? I am about to start rebuilding my engine in December (waiting for Waynes book to come out) and from 101 projects and a tech article on pelican parts I thought that cam timing was not suppose to be a difficult task. Now I'm extremely nervous about doing this job myself. I understand all the articles I have read on doing this but still am very hesitant.

Hoping everything turns out ok for you KC.

I would have to say yes it is possible to damage the valves if you turn the engine by hand but if your half carefull you shouldn't have a problem.

I followed the 101 book and turned the cams out of the way slightly so I could rotate the crank with a spanner. I did at one point feel some resistance but I was turning the engine very slowly, so all I did was back it of slightly and rotate the R/H side cam back to its original position and tried again.
There is no way I could have done any damage.

The only thing I did find was when turning the cams they are heavily sprung due to the valve springs, thus the cam wants to turn back to its original place.