Thread: carb and rear question

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About the spacer: If it's a 4-hole spacer, it'll help the fuel/air mixture make the turn into the intake runners instead of slamming into the floor of the intake manifold when it leave the carburetor bores and I'd leave it in place. If it's an open spacer, then it has effectively turned your dual-plane (180 degree) manifold into a single-plane (360 degree) manifold. This is assuming you have a dual-plane manifold in the first place. A 360 manifold is normally used where you have a large displacement motor or are revving a small displacement motor to the moon because each cylinder "sees" the entire volume of the manifold. With a 180 manifold, each cylinder only "sees" half the manifold volume, so cyinder filling and throttle response is better with a low-rpm (street) motor.

I agree that a gear in the "4" range will be a bear on the street and you probably won't like it much if you're over the age of 17 . It will provide ear-to-ear grins though, at least until you pull up to the gas pumps. A change to something in the 3.50 to 3.70 range will make you think you've bolted another motor into the car and still provide a modicum of fuel mileage.