The guy at Kragen recommend that I use a can for motor oil flush before I switch to synthetic.
Is that a good idea?

 

No idea why you would do that. Modern synthetic oils should be 100% compatible with non-synthetics. At least Mobil 1 says so on the bottle.

But I guess you could check your Amsoil to make sure.

Peter

 

This is the typical Amsoil sales pitch. I made an enquiry about getting some Amsoil a few months ago. Not more than 2 minutes into the phone call, they tried to convince me that to switch to Amsoil, I must do the complete "package deal" in order to get the full benefit of using their oil. I would have bought their oil but that sales pitch completely turned me off. It was like they were trying to indoctrinate me into AMWAY.
I've been using Mobil 1 for 2 decades and none of my cars have suffered any ill affects from it.