How to set timing when timing marks are blocked?

351w, timing marks are on pass side of engine, however, water pump hose comes off same side, blocking off view to set timing. I set by ear, seems to run fine, not sure if it is at its optimum though. Thoughts?

Rotate the crank until it is at TDC on compression stroke for cylinder number one. FInd a location where you can see the damper, and then make a pointer out of sheet metal using a front cover bolt to secure it. Be sure it can’t move around. Mark the damper corresponding to the pointer. Now you have TDC. If you have moden timing light that has a dial on it, you are done. Other wise find the original timing marks on the damper. It will show 0 and a few other points. Put a piece of masking tape in the damper long enough to reach all the timing marks. Make lines on the tape corresponding to the timing marks. Be sure to mark TDC (0) very clearly. Peel off the tape and then line up the TD (0) on the tape with the new TDC (0) you just created. Then copy all of the other marks. I use paint pens in red white and silver. I typically use the red one for my target of say 10 to 12 BTDC.

Great idea! Thank you!