This is not a definitive answer; just the fruit of some research. Someone else might be able to provide an authoritative answer if they know it. :)

I've found the band you mentioned (on Facebook and their website). And the same name shows up in Danny Gatton's discography, too.

The 1932 Ford is known as a "deuce". So, "Cruisin' Deuces" is very likely to mean (literally) "Some 1932 Fords that are cruising", where "cruising" means "driving around the streets fairly slowly in a casual fashion, more than likely at night". This is what I suspect the band's name means.

Another lead is a book called "Cruising the Deuce" by Allen Windsor. In that context, "The Deuce" is the name of a theater. And "cruising" is referring to going out in search of casual romance (I'm being euphemistic). This is interesting, but I feel that it's less likely that this is what the band's name is referencing. However, I wouldn't be surprised if it's a mix of the two.

Hope that helps!