'68 318 to carbed Magnum 5.2: Check my checklist
If you want to use the magnum fan, you have to use the magnum front dress (water pump, timing cover, etc)...it's threaded on to the water pump stubshaft, so unless you modify the fan/clutch assembly to fit an LA style pump, it won't directly bolt on. A factory A body LA fan shroud fits since you'll be bolting on LA style accessories.
I don't have the ps pumps in front of me, but if you don't have a saginaw style pump, I'm pretty sure it won't be a bolt on affair--do you have a shop that can make you some lines? Or if you have a legit parts store near you, they have books that you could probably sift through and find one with the correct ends.
737jetdr--if you're swapping from a 318 to a 5.2, any 318 LA flexplate will work with the 5.2/904--it's the same internal balance, no need to use a different one unless you need the magnum flexplate for the EFI swap...that's a whole different story. I have the stock '72 318 flexplate on my 5.2/904, and it bolted on no issue.
If you get a 360LA that's a little different, but B&M makes a the counterweighted flexplate so you can use a neutral converter. If you have a 360 available to you, and it's a good price, I'd almost say go that direction.
here's the flexplate for the 360LA/904 swap:
http://www.summitracing.com/parts/bmm-10239/applications/make/dodge?prefilter=1