You will also need a different carburetor. Carburetors for engines with automatic transmissions are calibrated 1/2 size to 1 size RICHER to compensate for the fluid coupling heat losses (one reason why an automatic will never get as good mileage as a manual with the same gearing). Failure to change carburetors will result in major idle issues.
Have never gone this way, but have made many conversions the other direction (remove automatic, install manual). Average fuel economy saving with the manual is 15~20 percent.
Jon.
