I have just torn all the way down to the head gaskets and am getting ready to replace them and start the re-build.

I want to double check this -- I have the crank shaft gear at TDC and the number 1 piston is absolutely at TDC. When I replace the sprockets on the cam shafts the mark on the sprocket just needs to be center between the marks on the head. Correct?

At that point do you just begin to work the tensioner back into the equation? What is the science involved in the proper ammount of tension?

Thanks.