Manifold For Twin HS6 SU Carbs: Rootes 2267cc As in Sunbeam-Talbot 90
The body of the manifold is made from 2 inch plumbers pipe about 2 1/2" inches long. Four pieces are cut to length and then cut with and angle lengthwise. Cut so that when laid side by side they can form two "V" shaped pairs with one opening at one side and the two at the other.
The flange at the carburettor end is cut from 1/8" sheet steel using a carburettor mounting gasket as a pattern.
The balance tube between the two manifold bodies is cut from 1/2" plumbers pipe in an inverted V form so as to clear the exhaust headers.
The two passages through the manifold bodies are lined with cones made of beer can stock so as to form a smooth channel from farburettor to cylinder head with no sudden changes in diameter (photos 2 and 4)
The metal parts are epoxied together and then welded. Make sure there are no air leaks.
The airbox is made from wood, sheet aluminum, and rubber weather stripping with two K&N circular filters inside
The choke actuaing mechanism is made from hardware store angle iron, aluminum strip stock, and picture hanging wire.
The modification has worked out well. When combined with a two inch dual exhaust, and a full Bamforth transmission with overdrive installation, the car becaomes a pleasant, stylish cruiser.From a letter by George Roberts
The twin SUs are mounted in reverse Left is Right, Right is Left. An extension of the linkage was construsted from brass stock.