Remove the fuel pump, distributor, and all the valve lifters, making sure to keep up with the position of the lifters. There is a thrust plate that positions the cam in the block, held by two screws. They're accessible through holes in the timing gear. The lifters MUST go back onto the same cam lobe they have ben running on, or the cam will wear out in a very short time once you get the engine running again. How do you intend to get those two bottom bolts back into the timing cover?
Now, having said that, if a mechanic working for Dad back in the 1950's couldn't change a timing gear in around 4 hours, he wouldn't have a job the next day. There's no need to remove the cam. Drop the oil pan to access the bottom two timing cover bolts, remove the harmonic balancer and timing cover, and break the remains of the fiber gear off the steel hub with a big pry bar. Use a hammer and chisel over the keyway to split the steel hub. Remove the fuel pump and use a pry bar to hold the cam forward against the thrust washer while you hammer the new timing gear onto the cam. Be sure the timing marks are aligned as you install the new gear, and button everything up. It's lunch time by now, so take a break, come back to the shop, and log a few more flat rate hours before quitting time.
That's how the stovebolt mechanics did it 70 years ago!
Jerry
Edit: It's also a good idea to replace that fiber gear with an aluminum one. You can heat that gear up to around 350 degrees or so on a BBQ grill to expand the center hole, and it taps on a lot more easily. Just remember to use welders' gloves to handle it while it's hot.
