i installed a dual setup this summer on my 54 3100 i wish i had installed the proportioning valve at the time. i still have lock up problems but i have disc/drum setup. cost wise they run about the same. brotherstrucks.com, fatfendered are two places. hope this helps. i try to say money and usually cost me more in the long run. i had professionals to it and still have problems. but they did what i asked. ron
