Cam Question for a 360

If you're going to upgrade to a 360, don't buy a cam based on your 318. I run an old Mopar Purple Shart .484 cam in my 360 and it has treated me well over the past 18 years, but there are much more modern grinds availabe now. A couple that come to mind are the Comp Cams 274 or 278 grinds. I'm not that familiar with the Crane cams, but Rumble is, so I'll let him give a recommendation on those.
You are right about that manifold in that it won't work very well with 360 heads since the ports are made for the 318. I run the LD340 on my 360 and it's a perfect manifold for my combination. The Air Gap is a great choice for a 360.
I'm like Rumble when it comes to lifters, I've used old ones but I don't recommend it since the cam and lifters should break in together. Also, get the proper valve springs to match the lift of whatever cam you finally choose. With highway type gears and a stock converter, don't get too carried away with the big numbers in your cam selection or your car will be a dog off the line.
Your stock valve train should be O.K. for your combination on the street. You don't need adjustable rockers, and unless you have the heads milled excessively, you won't have to worry about pushrod length, just use the stock ones. Your rockers will probably be the age of your motor, so it's up to you if you want to replace them. I'm still using the original 1978 rockers on my 360 and haven't had any pushrods go through them as yet.
The parts you've bought are all correct for what you want to do. Keep your 904 tranny and just bolt your 360 up to it and go. Good luck.