LA 360 roller engine ?

A couple of things you'll need to address:
1.) Oil pan, pickup, and dipstick. You'll need to swap on the passcar units.
2.) As mentioned, the mechanical fuel pump mount. I've seen them two ways: either with a blockoff plate or with an unfinish-machined mount. From what I've seen, the 318s have a block-off plate and the 360s aren't finish machined- but don't quote me on that. The unfinished one is easy enough to open up and use, though. Either way, you'll need to get in there and confirm whether it has an eccentric on the cam gear- some did and some did not. If it does, you're ready to rock. If it doesn't, it's easy enough to add but you'll have to pay attention to a couple of things. There is a special cup washer used on the "eccentric delete" motors that is deeper than the standard cup washer used on long-nose LA cams, this makes up for the extra spacing that the eccentric would have provided had it been there. Do NOT use this cup washer if you add an eccentric to the cam- it will not allow correct tightening/spacing onto the cam. Source a standard LA washer to use instead.
Standard LA on the left, eccentric delete on the right:
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Don't confuse either of these with a Magnum washer for a short-nose cam, which is almost flat.
If you've got it open to add an eccentric, throw in a new chain & gears, and new front seal.
3.) You'll need to address the balance issue with the torque convertor by using the correct B&M flexplate for your transmission- 904 or 727. If it's an original '64 trans (904) you'll also need the crank adapter bushing because of the difference in diameters between early and late convertor noses and crank pockets.
4.) Don't forget to drill, tap (1/4-20), and plug the air injection holes beneath the exhaust ports.
5.) Depending on what engine it's taking the place of and your current setup, you may need to swap to an early water pump to work with your radiator, and don't forget the different depth pulleys that go along with that...
6.) Before you install, check your starter fit- some of these roller blocks had an additional boss behind the starter (used during production) that interferes with some year starters- grind it down if necessary, easier to do before the engine is installed in the car.
And while we're talking about bosses, double check clearance behind the newly-installed fuel pump- depending on the pump you use (mostly the large diameter Carter HiPo pumps and it's clones) there is a small casting bump on the block that may interfere with pump installation and alignment that you'll need to clearance, two minute job with a grinder.