Carburettors are not rated by RPM
There is a black screw behind the carburetor, if you turn it clockwise while it is idling you will hear the rpm's drop.
Dirt.
The RPM range for a MerCruiser 260 motor typically spans from 400 to 4,600 RPM. The engine is designed to operate efficiently within this range, with peak horsepower generally achieved around 4,200 to 4,600 RPM. It's important to consult the specific owner's manual or manufacturer specifications for the exact RPM limits for your model.
Currently the largest carburetor that Weber sells is the 55DCO SP. It has a retail price in the $450.00 range and is a two barrel side draft compatible carburetor.
Carburetor adjustment or if unattainable rebuild the carb. about $20 and 1/2 hr Before you start messing with the carburetor, check the air and fuel filters.
The 1978 Ford Mustang - 302 - 2 barrel carburetor - is rated at 134 horsepower at 3400 RPM and 250 ft-lbs torque at 1600 RPM
5000-6000 rpm
About 2300 to 2450 RPM (In that range) At 70 it should be around 2100 RPM.
That model has a max continuous RPM of 11,000, and a max RPM of 12,000
Ford used a 4180 Holley 4v carburetor built for Motorcraft. Rated at about 600cfm. That may seem small but stock 460's are seldom ran past 5000 rpm
750 to 900 rpm Whem it is warm, cold start 1200 to 14000 rpm
The most common range is 5400-7200 rpm. There are also 10000 and 15000 rpm drives. Solid state drives do not operate on the same principals as disk drives, and do not spin at all.