11. COMP supplied the entire valvetrain, including the XER281HR hydraulic roller cam and the retro-fit short-travel roller lifters. These lifters require precise pushrod length and accurate preloading but perform virtually like a solid roller lifter even at 7,500 rpm.
12. Installing the COMP cam with a smidgen of lube is sufficient since the engine will be pressure lubed before firing it for the first time.
13. The RHS block raises the cam centerline, which requires a custom timing chain with two extra links to maintain the proper tension. This was followed by the oil pump attached with ARP fasteners.
14. A balancer plays a critical role in damping natural crankshaft oscillations. The beauty of ATI's three-piece design is that you can match each piece specifically to your engine.
15. Before bolting on the heads, Clapp employed a set of Fel-Pro 0.053-inch MLS head gaskets to reduce the static compression ratio to 10.6:1.
16. Shaver Racing Engines supplied the CNC-ported production LS3 castings for our 427ci. The rectangle port heads are big as-cast, but you'd never know it by how much torque this engine makes.
17. Livernois says these rectangle port heads will flow 360 cfm on the intake side and with a 1-3/4-inch primary header tube the exhaust side will flow 275 cfm, which is an exhaust-to-intake relationship of 76 percent, which is outstanding given the big intake flow numbers.
18. The Stage 3 Livernois heads run 2.160 and 1.590-inch valve sizes to ensure excellent flow. The chamber size is standard at 70 cc.
19. With the large intake valves on the LS3 heads, this moves the valve and requires an offset rocker arm. COMP Cams has a very nice rocker shaft valvetrain for the 427 with the offset intake rocker using the stock 1.7:1 rocker ratio. The shaft offers substantial improvements in valvetrain stability over stud-mounted rockers.
20. A pro build means degreeing the camshaft to ensure that it is installed at its intended intake centerline. The COMP adjustable timing set made it easy to ensure the 109-degree centerline position.
21. COMP also supplied the front cover that includes the cam sensor and Clapp bolted it all together with ARP fasteners.
22. There are lots of reasons to use head studs instead of bolts, including consistent clamp loads. Never torque studs into the block, ideally they should be finger tight with full thread engagement. A portion of the stud thread should show above the deck. This ensures that the top thread in the block is not overly stressed.
23. Shaver also decided on a Mast Motorsports oil pan that would work well with the RHS block and also clear the crossmember on the Roadster Shop chassis. The pan is cast aluminum and is intended for use in autocross or road racing applications. Plus, it has a cast-in filter boss, eliminating the need for an external filter.
24. Rather than go with a mundane carburetor or factory intake for the 427, we chose an Inglese 8-Stack Induction System. The eight individual 50mm IDA-style throttle bodies each fitted with a 50-lb/hr FAST fuel injector. In addition, the fully assembled manifold is complete with installed fuel rails and an extremely precise throttle linkage system. Intake bells and filters were also part of our assembly.
25. Controlling the Inglese 8-Stack is a FAST EZ-EFI 2.0 self-learning EFI. The beauty of this system is that with just a few keystrokes, the system establishes the necessary parameters and the engine runs and quickly settles into the proper air/fuel ratios.
26. Clapp test-fit the intake on the engine to ensure everything bolted up properly. The Inglese 8-Stack intake uses O-rings instead of gaskets, which makes the installation on an LS engine nearly foolproof. The Inglese manifold also integrates a common chamber for the MAP sensor and idle airspeed controls that make running an individual runner manifold like this much easier. No more balancing throttle blades with a Uni-Syn!
27. The Vintage Air Front Runner accessory drive assembly comes with everything you need to install, including the water pump, alternator, power steering pump, A/C compressor, and all the brackets and hardware.
28. Installed on the dyno, the EZ-EFI 2.0 system fired the engine immediately and after a short engine break-in period, the engine was ready to impress. It only took a couple of runs for the EZ-EFI 2.0 system to dial-in the air/fuel ratio for peak power, making a best of 622 hp at 6,000 rpm.
29. Speedway Motors provided the LS finned valve covers while Lokar supplied the engine oil and the trans dipsticks.
30. During the assembly of any engine a great choice for engine assembly lube is AMSOIL INC. It will stick to components and provide rust and corrosion protection, will dissolve in engine oil, and contains antiwear additives all during the assembly and “storage” cycle before the engine is put into service.
31. Flowmaster LS block hugger-style headers (PN 814121) were used, giving plenty of clearance to the Flaming River steering and the Wilwood brake components.