I need help finding tdc

As far as TDC, the procedure is the same on anything. Make sure your on the compression stroke then rotate to line up the damper mark to 0.
Not correct. How do you know the timing marks on the damper, and timing tab are correct. Over the years the slant six had at least three different dampers and tabs. They will all interchange on the engine, but may or may not be compatible with each other and align at TDC. This must be verified.