Magnum going into '73 Dart...which spool mounts? Where to buy?

You guys are the best....thanks to each of you.

So based on the above, it sounded like I could reuse the passenger side mount but that I would need the LA 360 mount for the driver's side...but the autoparts store cross-checked the part numbers with the LA 318 mounts and said they were the same!

So now my plan is to try the old mounts from the 318 as soon as the Magnum motor is in my garage... I assume that the fitment in question is where the bracket bolts to the block (since the K-Member mounts are obviously not going anywhere...) So I should know right away.

Thanks again, guys.