Quote Originally Posted by matt5112 View Post
turn motor to TDC then put air in via the spark plug holes with an adapter.

Air compressor helps.

or you could do the string trick.
I wanted to add to this that you don't need to get the motor to top dead center. When I did my cam, I only pressurized the cylinders with air to hold the valves and didn't have any trouble. I bled the pressure into the cylinder slowly since it will push the piston to the bottom of the cylinder. After that it was just a few minutes to compress the spring, pop the locks out, remove the spring and retainer, replace the valve seal, and reassemble.