I need some 12v dc servo motors for an automotive project..

Basically exhaust cut outs, so the servo will simply open a butterfly valve, simple as that.

Being that it's an automotive project, would have to be 12vDC, needs to be smaller, probably less than 2.5" diameter, geared down and speed is not an issue. And must be able to withstand weather conditions, mud, rain, snow, anything the bottom of your offroad vehicle will see (intermittent, not submerged). That might be asking for a lot?

Anyone know where I can find these? It's pretty much a non-profit venture, doing it for a friend so low price would be nice.

And yes, i'm aware they already sell electric exhaust cut-outs, I just need to make a couple of custom ones and I figured it may be cheaper to start from scratch rather than buying them from Summit Racing, salvaging the servo and modifying them.

Thanks in advance, hope somebody knows something!