Macs with a 68040 processor are better. The 68030 processor based Macs are older and slower.

68040 Mac ROM dump files are usually 1 MB. 68030 Mac ROM dump files are usually 512 KB.

Examples of 68040 Macs that dump a 1 MB ROM file that work with Basilisk II:

Mac Color Classic
Mac LC III
Performa 460
Powerbook 180
Mac LC 475
Performa 475
Quadra 605
Mac LC 580
Performa 580
Mac LC 630
Performa 630
Centris 610
Quadra 610
Centris 650
Quadra 650
Quadra 700
Quadra 900
Quadra 950