The Ford 260-289-302-351 Windsor
The 90 degree V-8 small block
The first Ford small block was introduced in the new intermediate size Fairlane in 1962. It was designed to be a weight saving power plant with thin cast iron walls. Weighing in at 450 pounds, it was hundreds of pounds lighter than the big block motors. The first small block was a 221 cubic inch motor. The two barrel version was rated at 216 gross horsepower with 8.7:1 compression.
The new small block really didn't cause much enthusiasm for performance until the Ford team put one in the 1963 Indianapolis 500 race. The Indy motor had a larger bore (0.300 inch) punched out to 260 cu. in. The motor was stock except for a cast iron block and heads. The Weber carbs upped the horsepower to 375 on gasoline. This little Ford engine took Jim Clark to 2nd place and Dan Gurney to 7th. Ford was back in racing.
The next year gave Ford the platform to display their new small block motor. The first car to enjoy the now 289 was the Ford Mustang. Out on the west coast, a entrepreneur happened to convince Ford their new small block would be ideal to use in the AC Bristol roadster. His name was Carroll Shelby and he called his car the Cobra. A special high performance 289 was introduced. It raised the stakes by offering:
- Four barrel manifold and carb
- Mechanical solid-lifter cam
- 10.5:1 compression
- Finned aluminum valve covers
- 271 Horsepower
Mid 1965 Ford changed the bellhousing from a 5-bolt to a larger 6-bolt. All 221, 260 and early 289's had the 5-bolt, later 289 and 302's got the 6-bolt.
A special Indy 289 motor was developed by the Ford engineers. They took a 255 cu. in. small block motor with an all aluminum block and added some real special heads. The heads contained four valves per cylinder, a set of overhead cams and Hilborn fuel injection. Even though quite exotic for the times, it was a successful race engine.
The 302 version was introduced in 1968. It replaced the 289 small block. That year a high performance 302 was not offered in the production cars. Ford was looking for a higher output small block though. The first attempt with the 302 was the "tunnel port". Copied from the 427 NASCAR heads, the intake push rods ran through a small tube in the head, surrounded by huge intake ports and valves. The motors were used in the Trans Am/Series II racing with mild success. The gains just weren't there from those exotic heads.
The next year, 1969, Ford came back with a better designed head. This head design had canted-valves, placed at an angle, allowing for larger intake and exhaust valves. It also created a semi-hemispherical combustion chamber. A special block was used with the heads. Ford called it the Boss 302. In addition to the heads the Boss 302 had:
- Four bolt mains
- Forged rods
- 10.5:1 compression
- A special windage tray in the oil pan
- Dual point distributor
- 290 degree duration solid lifter cam
- Aluminum intake manifold
- Huge 780 cfm Holley four barrel carb
And Boss it was. The Boss 302 was a close as you could come to buying a racing engine in a street car. /Lin
Also introduced in 1969 was the last version of the small block 90 degree V-8, the Windsor 351. The block was entirely different than the 289/302. The main differences between the two motors are:
- Unique intake manifold
- Changed firing order
- Longer stroke (4.00 inches compared to 3.50 inches)
- Better main bearing structure
- It is taller than the 302 causing the cylinder heads to be farther apart. (1,275 inch higher deck)
- Larger rod journals
- Larger main journals for rigidity (3.00 inch)
- Different heads but can be used on the 302 and 289
- Larger head bolts (1/2" versus 7/16") with an extra head bolt and different water passage
- Larger Intake (1.84") and exhaust (1.54") valves
- Larger combustion chamber - quench type rather than open-chamber
- 10.5:1 compression
- The 4 barrel was rated at 360 horse, 320 for the 2 barrel version
In 1971 the 4 barrel 351 Windsor motor was eliminated from the options list. The 2 barrel compression dropped to 9.0:1 with a decrease in horse power to 240.
Source: A great book on Ford motors called Ford Performance by Pat Ganahl