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Gents,Here is some info on putting twin carbs onto a Subaru EA81 engine, specifically Weber CH34 Single Barrell Downdraft Carbs.Attached are some pics of the build on the engine and a 3D CAD image of the adapter.There is a 25mm copper tube joining the adapters below the carbs, so each bank of pots can suck air / fuel through both carbs at once. I"m yet to put a vacuum gauge on it to see how well balanced it is. The coolant flows through a slot up into the adapter and out into an equal length tube to the top of the radiator.I did this as the old manifold rotted out for the dual throat DG3228 single weber dual throat carb I had on the gyro before. It needed replacement.I put them on and plumbed it all up and got a start out of it first go, but it didn"t rev past 2000 without the choke on,. it was jetted up with 130 main jets.After a series of trials I"ve ended up with 155 jets, the motor outputs 4600 RPM at WOT running a 72" warp drive three bladed prop. It"s hell scary and can snap from idle [600] to 4000 in less than a second :-OI"m very curious to see what happens when some real flying happens with this set-up, on the ground it is very impressive.Cheers,Nic.