Strange thermostat size on a 390 engine

usaimages · Post by **usaimages** » Wed Jul 29, 2009 5:04 pm

I don't know what gives, but here is the problem. I went to replace the defective thermostat in my F100 with a 390 engine. The parts book comes up with a Stant superstat that is too small for the stock intake housing. The old thermostat is 63mm and the new one is only 54mm. The application book says that part # 45359 is the correct one. What gives?
Before anyone comes back with the obvious - you sure it is a 390, the answer is yes it is.
Any help will be greatly appreciated. Thanks!

BobbyFord · Post by **BobbyFord** » Wed Jul 29, 2009 5:49 pm

The larger t-stat is for an early intake.

TNIceWolf · Post by **TNIceWolf** » Wed Jul 29, 2009 6:07 pm

I was talking to one of the old time hands at a local parts store when i was replacing my thermostat. Apparently there was some sort of adapter plate in the older models which required two gaskets.One for the adapter to housing......the other for the adapter to thermostat.
That allowed for adapting the two together. Mebbe you could just use the housing for the size that fits the intake? or find the adaptor?

convincor · Post by **convincor** » Wed Jul 29, 2009 9:16 pm

the earlier large thermostat is the same as a Mopar. Just ask for one for a 71 plymouth Fury with 383.
Or just look up the application for 64 t-bird, 390.
No adapters needed.
Here's the one you want- http://shop.advanceautoparts.com/webapp ... 9243941___

usaimages · Post by **usaimages** » Thu Jul 30, 2009 5:52 am

Picked up one for the early manifold and it fits just fine. Thanks for the help - it's really appreciated.

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Strange thermostat size on a 390 engine

Strange thermostat size on a 390 engine

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