1988 Ford Mustang Boss 302 Crate Engine

The Boss 302 arrives looking just like this. To get it running, you'll need headers, an intake, a distributor, and some sort of pulley system. These engines have "Boss" and a serial number stamped on the rear bulkhead.

The Boss 302 arrives looking just like this. To get it running, you'll need headers, an in

We love the Ford 302. Its short, 3.00-inch stroke encourages flinging the tach needle to 7,000 or even 8,000 rpm, and its fat, 4.00-inch bore allows mucho cylinder head breathing. We've punished a 5.0L from an '88 Mustang with a 618hp blast with an ATI centrifugal supercharger, and more recently, we plucked a junker 302 from a wrecked Ranchero and built our way to 479 hp using race gas and a gigantic solid lifter camshaft. You can't claim the engine isn't versatile.

Even though we've made good power with boost and octane, we've always known the core of the engine is based on a two-bolt main block and a nodular iron crankshaft. We've proved the short-block's resistance to short blasts of boost and rpm on the dyno, but what about street longevity? At 7,500 rpm, the crank is squirming around and the caps are moving. That eats bearings-and eventually something will fail.

The meat of the Boss is the new block. It has an 8.2-inch deck height, and unlike the standard 302 or even the original Boss engine from the '60s, it has a siamese bore that can be bored 0.125 instead of only 0.030. The block is machined to accept factory roller lifter guides and lifter guide retainers otherwise known as the valley spider, and it has a cam retainer. If you bored this engine all the way to 4.125 and added a 3.400-inch stroke crank, the engine would displace 363 cid. It also has 1/2-inch head bolts if you want to play with some boost.
The meat of the Boss is the new block. It has an 8.2-inch deck height, and unlike the stan
The mains have splayed four-bolt caps on 2, 3, and 4 and two-bolt caps on 1 and 5. The main cap bolts have been upgraded from 7/16 to 1/2 inch in the center with 3/8-inch bolts on the outer locations. The block is made from diesel-grade heat-treated cast iron. Sounds tough, right?
The mains have splayed four-bolt caps on 2, 3, and 4 and two-bolt caps on 1 and 5. The mai
The Boss uses the Turbo Swirl Aluminum cylinder heads that have an advertised intake/exhaust flow of 240/170 cfm at 0.550 lift. They flow better than the original iron GT-40 heads and are 25 pounds lighter. They use 1.94/1.54-inch valves, have a 178cc intake and 62cc exhaust, and can use either the GT-40 manifold or aftermarket intakes, headers, and valve covers.
The Boss uses the Turbo Swirl Aluminum cylinder heads that have an advertised intake/exhau

That's why we were geeked when we heard about the launch of the new Boss 302, a sweet upgrade to our favorite small-block Ford engine. Not only does the new Boss have the nickname from the late '60s to wow the Mustang guys, but it also has a four-bolt main block and a forged-steel crankshaft to back it up.

The engine is offered from Ford Racing with a suggested retail price of $6,695.00. It arrives as a complete long-block with a rear-sump oil pan for the Fox chassis, a neutral balance 157-tooth flywheel, a balancer, a reverse-rotation water pump, Boss valve covers, and a dipstick. At the core is a new production iron block with splayed four-bolt main caps that can be punched to a bore of 4.125 with a maximum stroke of 3.400. It has a steel crank and rods and forged 9.0:1 pistons. You also get either the B303 hydraulic roller cam ground for manual transmission or the E303 hydraulic roller that is recommended for automatics or manuals.

We tested the Boss 302 crate engine with three different intakes to make the selection process easier for you and to see if it made the advertised power. We also wanted to see if we could improve it a bit without wrecking the 12-month, 12,000-mile warranty. Check it out.

What's The Diff?
We thought to show you the differences between the stock 302, the '69 to '70 Boss 302, and the new Boss blocks.

	Stock 302	’69-’70Boss 302	FR Boss 302
Main caps	Two-bolt cast iron	Four-bolt cast iron	Four-bolt nodular iron machines splayed
Siamese bore	No	No	Yes
Freeze plugs	Press	Screw-in tapered pipe thread	Screw-in O-ring sealed straight thread
Material	Cast iron	Cast iron	Diesel-grade heat-treated cast iron
Heat bolts	7/16	7/16	1/2
Maximum bore	4.030	4.030	4.125
Main bolts	7/16	7/16	1/2
Oil galley plugs	Pipe thread and press in	Pipe thread	Screw-in O-ring sealed straight thread
Hydraulic roller compatible	Yes	No	Yes
Clutch cross-shaft pivot hole	No	Yes	Yes
Rear main seal	One-piece	Two-piece	One-piece
Maximum cid	347	347	363

*Chart courtesy of Ford Racing

When you order the Boss 302, you get two cam choices. The B303 has 224/224 duration at 0.050 and 0.480/0.480 lift with a 1.6 rocker arm and is recommended for a manual transmission. The E303 has slightly less duration at 220/220 at 0.050 and more lift with 0.498/0.498. The B303 short-block comes with a flywheel and would likely be fine in front of an automatic transmission with a 2,000-stall converter. The real choice is whether you want to use it on the street. The E303 is emissions-legal using E.O. D-225-16.
When you order the Boss 302, you get two cam choices. The B303 has 224/224 duration at 0.0
If you want a little more, Ford also offers the CNC Z head. It flows 314/221 intake/exhaust at 0.500 lift after a competition valve job on the 2.02/1.60 valves. The intake port is 204 cc, and the exhaust port is 160 cc with a 63cc combustion chamber. It will make a lot more power without increasing the compression ratio.
If you want a little more, Ford also offers the CNC Z head. It flows 314/221 intake/exhaus
For testing, we used the MSD billet distributor that includes the steel gear you'll need for the roller cam. Flat-tappet cams use cast iron, and billet rollers use silicon-bronze. The firing order for the Boss 302 is 1-3-7-2-6-5-4-8, the same as the 5.0L H.O. and the 351W. All the tests were run with 37 degrees of timing on 91-octane pump gas.
For testing, we used the MSD billet distributor that includes the steel gear you'll need f