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Ford 302 Engine

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Ford needed a bit larger engine to race in the Trans-Am series. Trans-Am racing was taking what looked like a street car and taking it racing. The rules allowed the maximum displacement to be 302 cid. The 289 block was given a longer stroke producing a 302 displacement engine. This engine was offered by Ford until 1995 when the direction became the modular blocks.



Ford Oval icon302 "F" 2V

1968-1973
302 "J" 4V

1968
302 "G" 8V

1968

Tunnel Port
302 "G" 4V

1969-71#

Boss 
Engine Type8 cylinder

90 degree,

Overhead Valves (OHV)
8 cylinder

90 degree,

Overhead Valves (OHV)
8 cylinder

90 degree,

Overhead Valves (OHV)
8 cylinder

90 degree,

Overhead Valves (OHV)
Displacement302 cu.inches (CID)302 cu.inches (CID)302 cu.inches (CID)302 cu.inches (CID)
Maximum torque

310 lbs./ft. @ 2,800 RPM

(1968)

295 lbs./ft. @ 2,600 RPM

(1969-71)

242 lbs./ft. @ 2,000 RPM

(1972-73)


310 lbs./ft. @
2,800 RPM
310 lbs./ft. @
2,800 RPM
290 lbs./ft. @
4,300 RPM
Maximum Horsepower210 BHP @ 4,400

(1968)

220 BHP @ 4,600 RPM

(1969-70)

210 BHP @ 4,600 RPM

(1971)

141 BHP @ 4,000 RPM

(1972-73)
230 BHP @ 4,800 RPM


250 BHP @ 4,800 RPM

(Shelby Cobra GT 350 only)
240 BHP @ 5,000 RPM


420 BHP @ 8,000 RPM

(Trans Am Version)

290 BHP @ 5,800
RPM


470 BHP @ 9,000 RPM

(Trans Am Racing Version)
Firing Order1-5-4-2-6-3-7-81-5-4-2-6-3-7-8 
1-5-4-2-6-3-7-8
Bore & Stroke4.004" X 3.0028"4.004" X 3.0028"4.004" x
3.0028"
4.004" x
3.0028"
Compression Ratio9.01:1

(pre 2/68)

9.51:1

(2/68 to 1970)

9.01:1

(1971)

8.5:1

(1972-73)
10.1:1 10.5:1  10.5:1
(1969-70)
Compression Pressure 130-170 psi    
Mains2-bolt2-bolt 4-bolt cross
bolted
Carburetor

Autolite 2300-A (2V)


 automatic choke

Autolite 4300
(4V) 


automatic choke


Autolite 4300-A (2x4V)

 automatic choke


Holley 4160 (2x4V)

manual choke
Holley 4150-C
(4V)


manual choke
Size of Carburetor    Autolite 435x2
CFM


Holley 540x2 CFM
 
Fuelregular gaspremium gaspremium gaspremium gas
Intake Manifoldcast ironcast iron


aluminum

(Shelby Cobra only)
special aluminum with pushrods
in intake
aluminum
Valve trainhydraulic liftershydraulic liftershydraulic lifterssolid adjustable lifters
Intake
1.773"-1.788"

1.773"-1.788"


2.01"2.225"
-2.375"

(1969)

2.185"-2.195"

(1970-71)
Exhaust1.442"-1.457"1.442"-1.457"1.53"1.647"-1.662"

(early 1969)

1.7075"-1.7125"

(1969-70)

1.7045-1.7145"

(1971)
Distributorsingle point

vacuum advance
single point

vacuum advance
single point

vacuum advance
dual point 

vacuum advance

RPM limits 

 5,950-6,050

(1969)

6,050-6,150

(1970)
Point Gap.017"-.021".017" for IMCO

.021" for Themactor
 .020" both sets
Initial Ignition Timing6 degrees6 degrees 16 degrees
Dwell @ idle RPM24-29  (manual)

26-31 (automatic)
26-31 for IMCO

24-29 for Thermactor
 30-33
Spark PlugsAutolite BF-42

(1968-70)

Autolite BRF-42

(1971-73)
Autolite BF-42Autolite BF-42Autolite AF-32

(1969-70)

Autolite ARF-32

(1971)
Plug Gap.032"-.036".032"-.036" .035"
Long Block Weight

in lbs.
475 475475500
Tunnel Port 302 

After winning the Manufacturers Trophy in 1966 & 1967, the Ford team had some stronger competition for 1968. Chevrolet
was about to get involved in a very big way. Vince Piggins at Chevrolet saw the great potential for sales of Camaros by racing in
the Trans Am series. He committed to SCCA that Chevrolet would support the series.


The 302 Camaros had a clear horse power advantage over the Mustangs. The ports and valves in the 289 heads were too small
to produce the horsepower needed. The best head available was the high
performance heads with small valves and ports. The new Ford 302 would be ideal for Trans-Am racing since it
was under the 305 cid limit of class limit, but the hi-po heads would be
too restrictive on the longer stroke of the 302 block. Ford started a crash development program to fix the problem at Ford Engine and
Development during 1967. This effort would lead to development of the Boss 302 in 1969. It was also during this development
time that the famous Ford "tunnel port head" came about. There was a
"pull out the stops" effort to maximize the flow of the heads. The Ford engineers developed a brand new head with straight intake ports and the pushrod tubes running through the
port. In the past the ports would twist around the pushrods. The intake valves were a huge 2.12" compared to 1.77" for the 289.
The exhaust valves were 1.54" versus 1.44". Each port feed an individual cylinder. These heads became known as "tunnel
ports." On paper this combination of the head design with the new 4 bolt main 302, looked unbeatable.

The overhead valve pushrod engines competed for space with the intake ports. Conventional design places the pushrods along side a rectangular shaped intake port. These ports also steer around the pushrods. The Ford tunnel-port design runs the
pushrod through the center of a round intake port, within a thin wall tube. The ports flow better due to their round shape and straight path. This design was first used on the 427, and then in 1968 on a special 302. 


These round intake ports were 3.8 sq. in. in area at the intake manifold face. The Tunnel Port 302 cylinder heads feature 2.12" intake and 1.54" exhaust valves. By comparison, the 289
High Performance engine used 1.78" intake and 1.44" exhaust. These large valves completely filled the wedge shaped combustion chamber. The exhaust ports
were larger than normal 289 & 302 heads. Two 540 cfm Holley's sat on a high-rise aluminum manifold.
Two Autolite 4300 carburetors were used on the street version. 


The race version featured domed pistons, yielding a compression ratio of 12.5:1, a solid lifter camshaft and forged steel crankshaft. The nodular cast iron rocker arms
were shaft mounted, similar to those used on the Y-block V-8. Lubrication for these shaft mounted rockers required a special block with revised oil
passages. Also used was a special road racing style 8-quart oil pan. Some used an early
transistorized ignition. 


The street version used flat-top piston, for 10.5:1 compression, and a hydraulic camshaft.
The engine was complete with thermactor emissions control hardware, 289
Hi-Po style exhaust manifolds, and a thermostatic clutch radiator fan.
SCCA rules required 1,000 engines in production for 1968 Trans Am homologation. As used in Trans Am competition the engines produced approximately 420 bhp with an 8,500 rpm redline 


You have to finish races to win them, though. The tunnel port engines just didn't have lasting power. Engine failure after engine
failure keep the Mustangs from finishing the races. Penske's Camaros dominated the 1968 Trans-Am racing. 


1968 Tunnel Port 302 Cylinder Head Casting number C8FE-6090-A 


The Boss 302


After a very disappointing 1968 racing season Ford designed a new engine specifically for F.I.A. Trans Am competition in 1969, the Boss 302.
The engine was introduced on April 17, 1969. About 8,600 Boss 302
engines were built. 


The Boss 302 block was essentially the next generation of 289 High
Performance hardware, but features a forged steel crankshaft, 4-bolt main caps, and screw-in freeze plugs. These modifications were developed as part of the 302 Tunnel Port design. Street versions used connecting rods similar to the 289
Hi-Po while the Trans Am version used heavier 7/16" bolts. 


The real magic of the Boss engines came from the canted-valve Cleveland cylinder heads. While the Boss 302
was normally considered a 302 with 351 Cleveland heads, these canted-valve heads were used first on the Boss before the rest of the Cleveland was developed. As fitted to the Boss, the heads feature steel spring seats, screw-in rocker studs, pushrod guide plates, and adjustable rocker arms. The Boss 302 and 351C-4V head casting
were the same except for a minor difference in water passages. Camshafts were quite similar to the 289
Hi-Po. Due to the larger Cleveland-style heads, the Boss 302 weighs somewhat more than the normal 302, tipping the scales at 500 lbs. 


The street version was conservatively rated at 290 HP @ 5800 RPM. During the '69 Trans Am season the racing engines were
putting out 470 bhp at a 9,000 rpm redline. 


Designed for the road racing environment, the engines featured a scraper style windage tray. This tray attached to four special main cap bolts with small threaded holes in their heads.