Raso Enterprise intake manifold heater for 240/300/4.9L engines - used

https://www.ebay.com/itm/134155368972?hash=item1f3c487a0c:g:20EAAOSw3zRirNY7

Interesting.  It says:

Raso enterprises intake manifold heater kit Ford 300 240 4.9L 6 cyl offenhauser. designed for use with the Offenhauser PN 6227 (1x4bbl) intake manifold and headers. This water plate bolts to the bottom of the Offenhauser 4 bbl intake manifolds allowing you to use hot coolant to warm the intake in colder climates for better drivability of your modified Ford 300-6 engines. This one was used with factory Split EFI manifolds so it was ground down on one side for clearance, it still functioned and sealed properly. Does Not include the 3  bolts for mounting to the intake.

Might be pretty handy if you had that intake.

Yep. Carbed I6 intakes bolt to the stock exhaust which contains a stove to heat the intake. If one moved to aftermarket headers (or EFI manifolds), there's nothing to heat the intake which can be trouble for carbs in cold temps; this "fixes" the issue.

Gary Lewis wrote

Might be pretty handy if you had that intake.

The Offenhauser is often listed as being able to use with stock log exhaust manifold [who would do that?], so the Raso most likely will work with stock intake manifolds.

1986F150Six wrote

Gary Lewis wrote

Might be pretty handy if you had that intake.

The Offenhauser is often listed as being able to use with stock log exhaust manifold [who would do that?], so the Raso most likely will work with stock intake manifolds.

Yep it will work with the factory log intake manifold.
I think that is who I got mine from off ebay back in the day.
Dave ----

That's why I said "carbed" intakes... Offy or stock. If using an aftermarket TBI solution (such as a sniper on a 4 barrel Offy), you don't need this adapter as the EFI system will compensate for the IAT automatically. AFAIK the intake side is sealed... it's the exhaust side that can be open when the exhaust stove valve is opened by the bimetallic spring (which is why there's an exhaust-style gasket between the exhaust and intake).