I have a homemade manifold with triple Weber 32/36 carbs on a 302 GMC. It is a scaled up version of the Harper. I made it out of steel exhaust bends, sheet metal and plates. Originally it had rubber hose ( 1 inch I.D.) connecting the 3 runners. I just finished welding all three runners together using 1 3/4 straight tubing. I did the basic design, cut out all the shapes and tack welded them together. A professional welder did the final welding.
As for as performance it does fine, especially when the secondary barrels come in. You can really feel and hear engine accelerate. I think it is because the runners provide a very smooth transition from two barrels into one. Also, the flow rates are always high because the runners have no extra volume to slow the charge down. It also pulls well at less than 1000 rpm in 4th gear.
I am not a wiz at posting pictures but I'll have my son help me tomorrow.
