Leaking Moen Kitchen Faucet

[bookworm]

My friend and I are trying to fix my leaking Moen kitchen faucet (single handle). It looks like it is pretty old. Probably from the 70's or 80's but when I did an internet search of the model number MT800 I came up with a very new modern looking faucet. Do they reuse old model numbers?

Also we could not get the diverter out/off. Any suggestions? We replaced the o-rings and put it back together and it's leaking worse than ever. I have to keep a towel wrapped around it when I turn it on. It does not drip from the spout. Just leaks alot around the base/handle area.

Any help would be appreciated.

Picture added. Might give someone an ah ha moment?