Join Date: Feb 2015
Location: Keene, TX
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3406B/C Combo Build
I am in the process of building sort of a FrankenCAT. I'm using a 4MG B model block and pump with a wide journal crank and rods. I have some questions about piston and nozzle selection. I was planning to follow Ynot's 625 C model formula. I am a little confused, however, since in the parts list it says that the pistons should be 14.5 compression ratio but when I talked to CAT the parts guy broke down the OR3783 cylinder packs and gave me the piston number of 7E-8656 which is a 15.6 CR. Maybe I missed something and transposed a number when talking to him or misunderstood the original parts list posted by Ynot. If anyone can clarify I would appteciate it. As far as nozzles go, will the OR8785s work with my pump? I did some reading that suggested that those nozzles pop at a higher pressure than the B pump operates at. If not are there nozzles that will work well with both my pump and those pistons or do I need to modify the pump?
Thanks in advance for any help you can provide.
1981 KW W900A, 3406A, 15 Speed
1986 KW W900B
1975 Ford F250 4x4, 12 Valve Cummins, ZF5, NP205, D60HP, Sterling 10.5
Last edited by Fordworth; 04-16-2017 at 05:55 PM.