Temp Sending Unit Question

[ChaseDale3and8]

Hey guys I have a question regarding the temp sending unit and what will work to make the guage work properly again. The engine I built and put in is a 1973 350. The 1986 temperature sending unit wouldn't fit as it was too small for the hole in the 1973 head, so I bought a sending unit for a 1973 truck with guages, and now my temp guage reading is way off to the right, so I figure the ohms must be way off or something. My truck doesn't run hot. I put a Mr. Gasket radiator cap with temp gauge in it on the radiator, and the truck has not been running over 180 degrees even on the hottest day. Is there a sending unit that will work from a different year that will fit the 1973 head, or a way to adapt my 1986 sending unit to the 1973 head? This is the last guage that I need to get working again since this engine swap. I finally put to rest the other electrical issues that I had last weekend when I rewired the engine compartment and put in a new ignition switch. Thanks in advance guys! ...Joe

 

[Boone83K10]

they have temp sending units that you can use to correct the problem. You just need to select the correct size along with the ohms that your gauge reads. I go the correct one for my truck which has a 70 350 swapped in.

 

[chengny]

Just use your original sender and a brass bushing to bring it up to the next larger size.

IIRC the correct bushing is 3/8 X 1/2 NPT.

Don't worry about the bushing - it will scew in almost flush to the head and the original sender will still be well positioned within the coolant flow. Use just a tiny bit of teflon tape or pipe dope on the male threads of each.

Your gauges will function as before and you can get your money back for the aftermarket sender.

I have bought many aftermarket senders that are NFG right out of the box - bring it back, slap it on the counter and tell them you went back to the OEM.

 

[ChaseDale3and8]

Thanks for the replies! I'm going to go to O'Reilly and see if those kids that work there have a clue what I'm talking about! That bushing sounds just like what I need to make the later sending unit work in the early head. I also liked the idea of using the size that would just bolt right in the head, but not knowing what ohm I need doesn't help and I thought that if I had gotten one for the 1973 head with guages that it would work. It didn't. I still have the original sending unit so I'll try the bushing! Thanks again guys!