Oh, heck, that's easy. If your car stalls when you stop short, you've got a Carter BBS or BBD or other carb with a front- or rear-hung float. If your car stalls when you make a hard left or right turn, you've got a Holley 1920 or other carb with a side-hung float.

Ross,

Having the carburetor's throttle shaft parallel with the crankshaft helps even out wet flow fuel distribution. With the carb mounted perpendicular to the crank you get wet flow off the throttle plates towards the rear of the engine. With the parallel throttle shaft the wet flow is more evenly distributed end-to-end. When I ran a 4bbl on a Clifford intake I mounted the carb with the primaries toward the left for this very reason. Pontiac did the same on their 4bbl OHC sixes. My end cylinders ran leaner (or was it richer? It's been a while.) than the center cylinders. Most folks with the primaries towards the front have lean front cylinders. I think a Hyper Pak intake would be less sensitive to carb orientation than the Clifford as the direction of flow within the manifold is more similar between the cylinders. The Clifford intake's end cylinders run fore and aft before turning toward the head and the center cylinders have a straighter shot. This difference in runners is much less pronounced on the Hyper Pak intake.

If you can get fuel distribution equal you can run leaner mixtures and get better economy before hitting lean missfire. My Clifford 4bbl combo would get a little bit of lean misfire on cold nights so I had to richen it up a bit. That's one big penalty of an unheated intake. Lean is ok at light load until you get misfire then the economy goes down the toilet.

So I vote for having the throttle shaft parallel to the crank.

Ok now I'm confused.

The super-six intake manifold had the holes perpendicular to the crank......


What 2-bbl manifold had them parallel????????

Oh, heck, that's easy. If your car stalls when you stop short, you've got a Carter BBS or BBD or other carb with a front- or rear-hung float. If your car stalls when you make a hard left or right turn, you've got a Holley 1920 or other carb with a side-hung float.

Oh, OK, gotchya, you're talking about what would happen if e.g. you took a 1920 or BBS and turned it 90 degrees so the bowl faced leftward or rightward. Under hard turns, you could have the fuel slosh away from the jet and starve out the engine.

Actually, I was thinking if you nailed it, you might uncover the forward jet...

H'mm. I can see that happening on a BBS, BBD or 1920 if you turned it 180° so the fuel bowl faced rearward. On the BB carbs, the effect would be especially pronounced because the acceleration would also tend to lock the float in the up/no-flow position.