Ford 302 Engine

Autolite 2300-A (2V)


 automatic choke

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.