Intake Spiders on small Continentals
The intake spiders as the carburetors on the small continental all fit, but are not that easily interchangeable.
The Early engine Series of the A65, 75 and A80 were fitted with a spider with a smaller throat. The smaller throat spider has a bevel on the outside that makes it easily detectable.
Spider for A-65 to the left, C-75, C-85, O-200 style to the right.
All C75/85 and 90 engines, as well as the O-200 are using a wider throat straight spider.
Spider for A-65 to the left, later style to the right.
If you happen to fit the smaller spider on a later engine, you are essentially throttling down the engine. Performance will suffer.
This happens more often than one would think. If you experience sluggish performance and have an otherwise good engine, check the intake spider.
Fitting a wider spider to an A65 on the other hand will not give you more power, since it is restricted by the carburetor's ventury.