GMC Other

I have a 1985 GMC Short bed pickup with a 305 in it. Trying to read the timing mark directly under the water pump is unreal. I took off the fan and water pump pully, all the belts, shroud. It has 4 V notches. Where is " 0" and 4 degrees BTD? There is a very wide notch towards the drivers side. Is that zero?

Thank you,
March 26, 2006.

Hey snowman, I'm not positive that gmc and chevy use the same, but if they are tdc (0) is the second point- not notch- from the drivers side going counter clockwise.4 degrees before would be the next point, the v-notch in between would be 2 degrees. See how it goes? The first point would be 4 degrees after. Next point 0, next point 4 before. This is on chevy but should work for you. And your right-It's a royal pain@$ ##$ to see sometimes! I don't know about wide notch unless someone has filed it. Look closely and clean it off real good and you might find
0 marked on it. Hope you get it. Burr

Me again, a little more checking around and I see that on some the wide notch is indeed 0 then it still goes 4 degrees for every point from there. Later

Mar 26, 2006.