Valve Block, Exchange. 10 solenoid, 11 port, This is the front and rear long valve blocks in the 392 / 394. Exchange means that you must return your defective valve block to us. The valve block you return must be complete and assembled. If you want to Exchange your defective valve block for a rebuilt valve block from us, DO NOT take your defective valve block apart. IF the defective block you return to us is not complete we will charge you for a new valve block. Prices are for work performed in our Depot in Newark Ca. Does not include shipping, insurance or tax if any is due.