Finally, my first 360 and goals for it! I'll be asking a lot of questions.

trebor75 said
I will be following 318willrunns porting videos and I will also have the heads milled. The shop who will be doing the milling, and taking care of some valve guides also clean the heads. I thought it would be nice to work on clean heads, but then I thought again... Is it better to do the porting first and then have them milled? When porting I will be moving them around a lot and it might be dumb to put the nice clean surface through that?

Car wash will get them plenty clean to handle and port. I wouldn't pay a machine shop to hot tank them before you port, because you'll want to clean them after you port for sure. The ones in the video, I cleaned at the car wash after they were all done. A messy job, though, as I high pressured every hole, port, guide, etc etc.....
And remember safety glasses.... :)