The part number you need is HP-CB-HP 10, if for a Ventura 200 or bigger, if its a 150 it's a 7 instead at the end. They are $500. Ish new for just the center block. I dont think they include piston lip seals
or pilot valve, definitely not a piston rod. You will need new lip seals
, and to switch over the other items, cylinders etc..
The cracking is from over tightening, I've seen many try to fix it with epoxy and it does not work
for very long if at all in most cases.
You can check Spectras website and see if there is a dealer near you.
If you can't find what you need I do have a refurbished Clark pump, 10% version I can sell and ship from Fl. Pm me if you need to.