Not directly, it will take a lot of modification, time and effort to achieve that swap.
Should drop right in...same engine.
I BELIEVE that is 4.5 quarts with engine oil filter change on the 1966 Ford Mustang STRAIGHT 6 cylinder engine
The 1990 Ford Mustang 5.0 liter V8 engine is rated at ( 225 horsepower from the factory )
It will bolt in, however, you will run into problems with the onboard computer. You will have to reprogram, or maybe even change it.
On a 1966 Ford Mustang : 200 cubic inch inline six cylinder engine : The spark plugs are gapped at ( .032 to .036 inch )
The point gap for the 200 cubic inch inline 6 cylinder engine in a 1966 Ford Mustang is ( .024 to .026 inch )
Five quarts with filter
The Ford Mustang GT has a V8 engine, while the Ford Mustang has a V6 engine.
The top speed for the 1966 Ford Mustang is around 150 to 170
My ( 1991 ) Ford Mustang 5.0 LX came from the factory with ( 5W-30 )
standard engine has about 280-345 horsepower ======================================================== A 1990 Ford Mustang 5.0 is rated at ( 225 horsepower from the factory )
The 2006 Ford Mustang has a V6 engine.