The keys to installing 351 Cleveland heads on a 302 block are making sure the water passages on the surface of each head are plugged, and passages are created (holes drilled) in the appropriate sections of the intake deck. We made the necessary modifications, but a discovery in Edelbrock's '08 product catalog proved to us we were slightly ahead of our time when we conceptualized our project. We mentioned Edelbrock's new E-Boss 302 intake manifold in our last story on our engine and explained how its unavailability led us to seek the assistance of Wilson Manifolds to create the Boss intake we're using. Well, Edelbrock has further simplified building a Boss-style 302. The company's new Performer RPM Cleveland heads (PN 61699; $979.99) mate perfectly with the E-Boss intake and are configured for 8.2-deck blocks. The eleventh-hour machine work we had to do isn't necessary with Edelbrock's matched set, but after overcoming the anxiety brought on by the need for custom work, it was fun figuring out how to make things right for our Boss 340.
Head studs are somewhat tricky with this type of engine build, as the Cleveland heads are much taller than most inline-valve aluminum heads that are used on street/strip engines. A big thanks goes to our buddy Ron Fruchey at ARP. He let us know that 20 of these 5.800-inch studs (PN AR5.800-1L; $6.52/each) are needed to get the job done. | 
Due to the 0.100-inch overbore and the possibility we may someday run nitrous thought our Boss 2340, we're using Fle0pro's large-bore, multi-layered steel head gaskets (PN1134) to maintain a good head seal. You may recall, despite torching the engine in our project T-top coupe 'Stang last year, its PermaTorque head gaskets remained intact and were not fazed by any of the chaos. | 
The cylinder heads are checked with this vacuum tester before they're installed. Probe developed this simple but effective (and cool) device, which pulls 28 inches of vacuum and can alert an engine builder of poor valve seal before the heads are installed. |
Probe's assembler recommends using a three-stage tightening technique for securing cylinder heads. After two tightening sequences of 45 lb-ft and 75 lb-ft of torque respectively, our engine's heads are locked down at a final 100 lb-ft before we move on to the valvetrain. | 
Probe's aluminum, stud-mount, 1.73 rocker arms open and close the valves. The "zero-lash" rules for valve adjustments apply to our engine because of its hydraulic-roller camshaft, so once each rocker is set (roller tips are squarely centered on the valve' tips), the adjuster nuts and poly locks are secured until the pushrods barely resist turning. A half0turn is then added to each assembly. | 
We need a timing cover that allows for installing a mechanical-style fuel pump, so FRPP's aluminum cover (PN M-6059-D351) is perfect. We install an 1/8-inch pipe plug to block off the hole for the dipstick tube. The bottom four front-cover bolts are 3/8-inch (for greater support around the crankshaft)and 5/16-inch ARP fasteners are used to fully secure the cover to the block. FRPP's SFI-approved crank damper (PN M-6316-A50) will keep crankshaft harmonics toned down. Its 50-ounce weight is removed, as our Boss 340 is internally balanced. |
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As we stated in the stories preceding this report, we want to incorporate new-school technology in our old-school-themed engine. This new electric water pump from Meziere (PN WP 311S; $424) carries that attitude to the fullest. It stock-style design allows the pump to be bolted directly onto the timing cover, without any additional adapters or plugs, for leak free water flow at 55 gpm. This piece is cool, and it really impressed our engine assembler at Probe. | 
Here's yet another old-school concept that has met the modern age. Our engine will be fed with this mechanical EFI fuel pump from Race Pumps (PN 1701; $329.95). The block-mounted timing cover pump is activated by the camshaft, and believe it or not, it's said to flow as much as 450 gph and support up to 2,000 hp. We won't make that much steam with either version of our Boss 340, but not hearing the drone of an electric pump will be kind of cool when we install our engine in 'Stang. |