just would like someone to help me out on my 2002 chevy blazer 4.3L vortec getting the engine back at TDC for cylinder #1 so I can install the distributor correctly. P1345 code is thrown everytime.

 

Best way I know is to pull out all the sparkplugs (relieves the pressure, makes it easy to turn) and pull the valve cover which houses the #1 valves and put a socket on the crank bolt and turn the crank by hand until both valves are closed on #1 cylinder. Then get a long straight piece of wood (a dowel is best but anything that won't scratch the piston or deform the sparkplug threads) and verify that the piston is at top of the stroke. You may need to move it up or down a bit to get it just right. You can use a screwdriver if you wish but just be super careful not to get it tweaked in the hole when you are doing your final movements to verify the piston is at the top of stroke.
Thats just what I do, someone else may have a better or easier way.

Hope this helps....