I am changing out modulators on my C3 and all the new ones I look at state different color stripes ie;red green-black etc What do these different color stripes equate too? Anyway I can't find any color stripe on my modulator and it has two (2) vacuum outlets (
Dual Diaphragm. I looked that up and those were only for a 1975-1977 model C3 tans mine is a 1978--does the
Dual Diaphragm make any difference? Can I run a modulator with just one vacuum?

?
thanks in advance,
Lefty