Thermostat By-pass Plate

Before you get too far in this, first is the engine overheating? The bypass plate is only needed if the engine is using a stock cast iron waterpump with a bypass channel built in, and many aftermarket pumps do not have this passage (such as the popular aluminum Weiand pump). Second, the "plate" is built like a freeze plug; it is slightly oversize for the hole, then is driven in and therefore distorts slightly. The diameter mismatch keeps it in place. With some care, a large std freeze plug can be modified with a 5/8" center hole to work with a 351C-specific thermostat, assuming you really need it. But wrecking yards are full of junk 351-C 2-V blocks with cracked cylinders, thrown rods etc. If I needed this plate, I believe i'd look there (with a big screwdriver to pop a used one out). Cost should be a smile & a handshake....Finally, some of the usual Pantera parts vendors stock a sort-of-replacement for this plate, or have scrapped engines around. Call around & inquire.

I didn't have an over-heating problem, this project started as a leaking orginal water pump, dated radiator and orginal fans that stayed "on" all the time. The new aluminum water pump I selected has the port for the by-pass. I didn't think to try a wrecking yard for the by-pass plate.(engineer out of control) I thought from the past posts that it was a preference to use the by-pass plate.

I also used your advice to make a custom shaped pipe to correct the coolant tank/pipe mismatch. I used 1 1/4" copper to fabricate it, but it substitutes the standard elbow in front of the oil pan.
Thanks for the help.

The only thing I might add, Jon, is, don't waste your time with tearing down 351-M or 400-M engines. In these crossbred truck motors, the bypass is cast iron, part of the block. M-series engines are 1" taller than the 351-C and theres a sort of rib above the thermostat area that doesn't exist in the Clevelands. Good luck-

I bought a couple from the ford dealer a while back, part # DAOZ-8K517-A . Hope this helps.

Thanks for the part number I also had it from some info on the web.

P.S. to Jack
It took me less time to fabricate one than finding and removing from a wreck. Thanks all!