The Sun 3/60, Sun 3/80 and (with expansion board) the Sun 3/50 can be upgraded with 30 pin SIMMs.
The SIMMs need an access time of 100 ns (or below). Look for marks like -10 (100 ns), -8 (80 ns) or -7 (70 ns) behind the type marker. Suns need true parity. That means the SIMMs must have 9 (simillar) or 3 (two simillar, one different) chips. Some SIMMs only simulate the parity bit, these cannot be used. Of course the ones without partity (8 or 2 chip) won't work too.
Since Sun3's are true 32 bit computers, the SIMMs must be put in in blocks of four.
Sun3's use SIMMs with a capacity of 1 MB. Only late 3/80 can make use of 4 MB types.