The greatest truck engine ever made.

Specifications

Bore & Stroke: 4.00" x 3.98"
Compression Ratio: 8.0-8.9:1

1965-1972
Brake Horsepower: 170 @ 3800 rpm
Torque: 283 lbs.-ft. @ 1600 rpm

1973-1974
Net Horsepower: 101 @ 3000 rpm
Net Torque: 223 lbs.-ft. @ 1600rpm

1975-1977
Some were the same as '73-'74 others
were bumped up to 120nhp @ 3400 rpm
with the same torque specification.

1978-1986
Horsepower ratings varied from 101nhp, 115nhp, 117nhp
and 120nhp @ 3000-3400rpm. Torque ratings remained
223 lbs.-ft. @ 1600 rpm.

1987 - 1993
Switched from carbureted to electronic fuel injection.
Compression ratio was 8.8:1
Brake Horsepower: 145 @ 3400 rpm
Torque: 265 lbs.-ft. @ 2000 rpm

1994-1996
Brake Horsepower: 150 @ 3400 rpm
Torque: 260 lbs.-ft. @ 2000 rpm

Perfomance Modifications

Carbureted

Air Intake: Most people seem to like K&N's, but any filter open
360* is an improvement over stock.

Carburetors: A Holley 390cfm 4bbl is the most popular choice and
works best especially with stock cam, a lot of people are happy  with
500cfm Edelbrocks too though. Only use a 4bbl with an Offenhasuer
or Clifford 4bbl intake, use a 2bbl with an adaptor plate.

Intakes:  Both Offenhauser and Clifford make a 4bbl intake for the 300.
Offenhauser seems to be the favorite because it's cheaper and just as good.
Clifford makes 2 and 3 carb intakes also.

Headers: Headman and Clifford are both good choices, ofcourse Headman is
cheaper.

Camshafts: Both Clifford and Isky make a wide range of camshafts.

Ignition: Any performance ingition, MSD is most popular.

Heads: You can have porting, polishing, bigger valves also putting on a
240 head will raise compression.

Exhaust: High flow mufflers, dual cats, no cats, hollowing out cats.
2 1/4" True duals with split headers is suppose to work the best.

Electronic Fuel Injection

Same kind of stuff except instead of slapping on a bigger carb, since fuel
injection doesn't use one, duh, you'll want bigger injectors and maybe you can
find a bigger throttle body that will fit.

Turbos: Some people have had custom manifolds made and used turbos of
Chevy deisils, there are no kits for this so it would be a custom job.

Chips: To my knowledge there are no performance chips for the 300.

Common Problems

Ford's 300 inline 6 is a fairly problem free engine for 200,000 to 300,000
miles if properly maintained. Common problems with the carbed models
are vacuum leaks, just little ones can cause hesistation, rough idle, etc.
The stock Carter 1bbl carb seems to like rebuilds too.  On the automatic
transmission models some people have problems with overheating, this can
be fixed with a cross-flow radiator and flex fan or a electronic fan.  Besides
that if their over reved the 300 is known to throw rods or have early valve train
failure.

I am not very familiar with the fuel injected models so I don't have a whole lot
of advise to offer with them

My 1978 F100 with 300 Inline 6 and 3.03 3 Speed Tranny, Indy floor shifter, 9" rear.