Re: A lot of smoke at engine start up. Need help!
If the smoke goes away after a few seconds and things get to temp, it's probably worn valve guides.
You may want to do a compression check and leak down test, could have worn rings or a collapsed oil ring.
I use valvoline 10w30 and have never had a cam go flat, everything looks like new.
Don't use lucas or any other additives except for maybe something with more zdp (spelling). I used lucas once, when I took of the pan, alot of it was still stuck in the bottom like honey, even when added to a hot running motor.
The only Mustang I'd ever own is a Fender.
'68 333" Camaro
'14 5.0 Mustang