Recommendations on a spacer to install a thermo quad on a 1972 340 intake

[Plymouth71]

I am looking to install a late '70s Carter Thermo quad onto a 1972 340 intake to be placed on my 318. What are your recommendations for a spacer, the linkages seem to be catching on the intake. Looking on eBay there are a lot of different options, but I don't know if I can trust the materials.

 

[Aron Gleason]

Phenolic spacers are good

 

[khryslerkid]

I used one from Summit. Wooden one, never had any heat soak problems.

 

[Orig69]

The original phenolic spacer comes with the carb rebuild kit sold by Mike's Carburetor Parts.

 

[493 Mike]

I believe FelPro sells a thick gasket. I just did a TQ rebuild for one of our members, using a Standard kit and it came with a thick gasket and two thin gaskets to use with the OEM phenolic spacer. FYI.
Mike

 

[T2R9]

As 493 Mike said, it needs the correct thick gasket. Felpro makes a nice one.

 

[Geoff 2]

If that lug on the intake, below the carb, is not going to be used, it could be ground/cut off for carb clearance.

 

[Rebelrouser]

I am looking to install a late '70s Carter Thermo quad onto a 1972 340 intake to be placed on my 318. What are your recommendations for a spacer, the linkages seem to be catching on the intake. Looking on eBay there are a lot of different options, but I don't know if I can trust the materials.

View attachment 1902174

View attachment 1902175

I thought 71 and later 340's used a thermoquad from the factory? I am building a 1971 340 for a customer in my shop right now and he has what he says is the correct manifold for his Cuda and it is a thermoquad. I bought a thermoquad off Ebay number 9055S which is a 1971 with a manual transmission carb, to use on the build.

 

[Plymouth71]

I thought 71 and later 340's used a thermoquad from the factory? I am building a 1971 340 for a customer in my shop right now and he has what he says is the correct manifold for his Cuda and it is a thermoquad. I bought a thermoquad off Ebay number 9055S which is a 1971 with a manual transmission carb, to use on the build.

My understanding is, that there may be differences with later Thermo quads. It might also be this one is off a big block.

 

[Vaanth]

I am looking to install a late '70s Carter Thermo quad onto a 1972 340 intake to be placed on my 318. What are your recommendations for a spacer, the linkages seem to be catching on the intake. Looking on eBay there are a lot of different options, but I don't know if I can trust the materials.

View attachment 1902174

View attachment 1902175

The area of conflict on the manifold is the mounting boss for the idle stop solenoid used on 1971 and 1972 340 Thermo-Quads. To mount any Thermo-Quad on the manifold, use a 5/16" spacer/gasket.

The following are some part numbers for 5/16" spacer base gaskets: Chrysler 3698365, 3879786, 3751286, Felpro 60273, Walker G897, Borg Warner 14279. The Chrysler numbers will only be found new as NOS (new old stock). .

The 5/16"gaskets generally look like one of these in the following image, except the lower right part:

The spacer/gasket on the lower left is the best overall design. It is a phenolic spacer with two thin gasket glued to it. This style was typically found in Hygrade kits by Standard Motor Products, and some others. It can be used alone or supplemented with thin gaskets if there is a sealing issue. The aluminum spacer on the lower right is a heat shield that was only used on the 1971 340 in conjunction with a thin gasket and an asbestos gasket. It could be used if you have one, with other thin gaskets, but it is only about 3/16" thick itself.

Although there are linkage variations, the later Thermo-Quad linkage sizing is not that different in the manifold conflict area pictured between later Thermo-Quads and a 1972 version. The following images show examples of early and late Thermo-Quad linkages on a stand with a wood block to highlight the area. I don't think I have a 1972 340 manifold, but I have some 1971 340 units, stored elsewhere, which are similar.


1972 Thermo-Quad for a 340:

1971 Thermo-Quad for a 340:

1978 Thermo-Quad:

1980 Thermo-Quad for IHC 345:

1978 Thermo-Quad on 5/16"spacer:

1978 Thermo-Quad on 5/16"spacer, different view:

Some thin base gasket (open) numbers: Chrysler 3879786, Fel-Pro 1902, 60273, McCord 66-0144, Victor-Reinz G14589 (G26662 for 1971-1972), Rol CM55011 (CM55256 for 1971-1972), Walker G897, Mahle/Clevite G14589.

For more information about Thermo-Quads, see A Carter Thermo-Quad Guide.