would like the tool that goes in the block to find top dead center?
This works great if you aren't too concerned about the accuracy. There is a dead zone at TDC. You can find the first point when the piston stops rising and then turn slowly until it begins dropping. Split the difference and that is approximately TDC. The bar and pin is dummy proof, which on an interference motor is preferable.ebay has them for sale with the cam lock bar as a kit. They can be purchased for less than $20.
on the same note, did you know that you can remove the #1 spark plug to locate TDC with something as simple as a long screwdriver?