I am using a homemade setup similar to this and it works very well on a mild 302 GMC. I used Weber 32/36 mm progressive 2 barrels. I made it from 3 90 degree mild steel tubing bends split horizontally and shifted to form the 2 to 1 taper. The 3 tubes are connected by 1 inch rubber hose to provide some balance a idle. It idles and accelerates well and gets 17 mpg on trips in overdrive pushing a 3400 lb 40 Chevy coupe.
