This 2-piece adapter will allow you to mount an IDA on an IDF manifold. Both metric (M8x1.25) and imperial (5/16 x 18tpi) mounting hardware is included. Every Weber manifold I've ever seen has had one of these two sizes. There is no gasket to go between the two pieces so you will have to use an RTV type sealant.
The demand for these has been very minimal so I only make them as ordered. The mounting on these will have the butterflies opening in the OPPOSITE direction if the IDF. I only mention for consideration of your linkage. Every time I make something I try to improve it a little so your's may not look identical but will be functionally the same. This item is in the category "eBay Motors\Parts & Accessories\Car & Truck Parts & Accessories\Other Car & Truck Parts & Accessories". The seller is "ecdezz" and is located in this country: US. This item can be shipped worldwide.