I went to Holley's website and searched based on the model rather than "Engine swap parts". Seemed to work better. But here parts that the engine swap category doesn't show.
Oil pans:
302-60/
302-60BK - non-VVT
302-61/
302-61BK - VVT non-HC
302-64/
303-64BK - Hellcat
Motor mounts only -
BHS571
Crossmember only -
BHS572
Headers -
BH23104
Note that I had to search on the part number for the headers, they wouldn't show up in the model specific search. And they only work on '73 and '74 <<wink>>.
Cast manifolds -
BHS582/
BHS584
Fuel tank -
19-135
Fuel tank module -
12-319
PS hard line kit (Borgeson) -
198-231
Dipstick -
302-74
The dipstick had to be search by part number like the headers, but it does show it is in stock. Note that I haven't tried it yet and I have heard of reports that it is too tall and doesn't bolt to the valve cover like it should.
There are other parts they offer like a hoop for a NAG1, the adapters for the transmission crossmember based on which transmission you are running and transmission mounts. But they seem to be easy to find for now so I didn't list them.
Note that some stuff does seem to have been discontinued. And the NAG1 hoop is only available as a white box (unpainted) item so I wouldn't be surprised if that didn't go away. It seems like they offered everything both coated and uncoated but a lot of the uncoated stuff is now disco'ed, so I am guessing that anything they offer uncoated only is there only until that stock sells out.