I need to know whats the best bike for start to have an original at the end
Not much to go on here, but the 71 looks like its a runner, the 74 not a runner.
On the 71, If there is a decent original exhaust under the non-stock black paint, you will be $$$ ahead.
The 71 looks like a repaint, the 74 original paint and dented tank, missing left sidecover.
74 has a replacement (alloy?) front rim.
...... and you will get more help posting in the tech forum (future project shop?) not introductions, and.....
welcome.