Keihins. Honda carbs that Ak Miller used to make 125 rwhp out the back of a 1967 Mustang 200.
http://www.jalopyjournal.com/forum/thre ... r8-6.5405/
Ak Miller fangle circa 1967. Four 37mm Keihin constant velocity carburettors from Honda 450 motorcycles were attached to stubs brazed to the cylinder head
Only he used just four 37 mm ones. Keihins go up to about 46 mm or so IIRC right.
The carb center spacings probably ape the center spacings of the nominal 3.387 or 3.383 bore to bore centers depending on which Kawaskai engine. Some are now making V8's out of these engines, Hartly make one, Synergy Power 2.4 and 3.0 V8's are basically a Kawaski 1200 that has hickups, and wants to be a simease bore Donovan SBC small block with multivalve heads. So its a down sized 4-1/8" by 2.85" F5000 racing engine, and instead of 275 thou of siamese metal between the cylinders, its cast linerless and tight at about 119 thou between the 3.387" bore spacing 83 mm 3.2677" linerless etch primed and coated cylinders. That's tight.
The Ford I6 log heads have a nominal 4.08" bore spacing, but differntial between ports as the center exhaust is siamesed, and as the triple SU intake shows, the ports are wildly off set to clear the exhaust. Fairly well typical of all the old in line sixes, set up to warm the single barrel carb.
The ports spacing from front to back averages 4.08 at the valves, but further out, from front to back, they are also additionally angled fore and aft, so the average center spacings are more like 4.222" at the carb centerline .
Nominally,
1 to 2 = 3.00"
2 to 3 = 4.00"
3 to 4 = 5.50"
4 to 5 = 4.00"
5 to 6 = 3.00"
