Am in the process of rewiring second series 55 chevy, pretty much stock with 235 / 3 on tree. Decided to change temperature gauge over to electric but just got the new sending unit and it is a sight larger than the original. Appreciate any input from someone who may already have figured this one out. Thanks, Frank
Frank - My name is Tom Duffy and I am new to the truck scene. I have a 56 3200 with 235. It has older heads and I found that the older truck used a mechanical guage with a tube to the guage. They had a 3/8" npt pipe tap size hole for the sending unit. The electric sending unit has 1/2" npt tap. I am rewiring my entire truck and ran into the same problem you have. A Note here: if you have a good mechanical sending unit keep it as they are hard to get -one intact. I researched many people to find something and a google search led me to the high performance Pontiac page where a fellow was discussing this very question. He had info on an older Ford 3/8" temp sending unit that had simular OHMs reading in the 160-220 range but not at the colder temps. This is the range that I was interested in anyway. This meaning the stock guage should read correctly where I want. I have purchased the sending unit from Napa and installed it but I have not got the wiring done to start the engine and test it. I took pictures and have the part numbers in my back garage. When I get it running , I will let you know how it works. If you would like the numbers before, let me know I will post them. Not and expensive part. It has a threaded top not the T top. Tom
Thanks Tom, I had hoped someone had already figured this one out, please post the part number when you have a chance. Thanks again, Frank
Frank- Like I said I have not got it running yet but it should work. Here it a link to pictures https://picasaweb.google.com/100461550391332593346/1956ChevyTruckWaterTempSendingUnit# and you should be able to get the numbers off the box. Note the correct sending unit is there also for comparrison. There are other albums one show the new mechanical sending unit for the car. I tried one but was unwilling to cut it up in order to fit the truck cluster. Hope this helps. Tom
