The heads are worth investigating more closely. Livernois starts with a pair of 821 LS3 rectangle port production castings. These are slightly different than the L92 rectangle port truck heads. The LS3 has a slightly improved intake port floor with a roughly 260cc intake port volume. Livernois applies a CNC porting effort to both the intake and exhaust ports, opening the intake up slightly, which produces a peak lift flow of 360 cfm, which is roughly a 10 percent flow improvement over stock. What is often overlooked with cylinder heads is how well the exhaust port performs. The exhaust cranks out a peak number of 245 cfm (275 if a 1-3/4-inch primary header pipe is used), which generates a very efficient 76 percent intake to exhaust ratio. This enhanced exhaust flow often contributes to excellent high-rpm power numbers. Combined with the Livernois heads is a set of Manley 2.160 intake and 1.590-inch exhaust valves that are basically the stock sizes. COMP then supplied a complete set of LS3 shaft-mount roller rocker package that uses an 8620 hardened steel shaft to create a very rigid mount for the 1.7:1 aluminum rockers. The roller trunion bearings and roller tips are both lube by an internal oiling passage built into the rockers. Combined with a set of dual springs, the valvetrain is more than up to 7,000-rpm escapades.
After engine builder Lee Clap assembled the RHS long-block, it was time for the induction system. Instead of settling for a carburetor or run-of-the-mill EFI, we opted to outfit our Road Tour 427 with a much more intriguing Inglese 8-Stack Induction. The intake centers around eight 58mm EFI throttle bodies that are designed to appear much like '60s-era Weber 48 IDA carburetors. Each throttle body is equipped with a 50 lb/hr FAST injector and connected with a complete fuel rail system that is visually downplayed. Buried underneath the intake is a series of internal passages that combine all eight stacks together to create a mini plenum that's used both to dampen the individual pulsations that can wreak havoc with pure individual runners. This common area also produces a convenient central point for both referencing manifold absolute pressure (MAP) and also for the idle air speed (IAS) motor that the computer uses to control idle speed. That way, when you crank up the Vintage Air A/C compressor, the FAST controller can easily compensate for the compressor load and maintain the desired engine idle speed.
This leads us to the brains behind controlling the Inglese 8-Stack. We could have gone right to the most sophisticated FAST controller, which would have been a logical step, but we decided to try FAST's new self-learning EZ-EFI 2.0. You might already know about the basic EZ-EFI 2.0 system that works with a single throttle body that replaces a typical carburetor. But FAST also makes a relatively affordable multi-point system that is designed to work much like the throttle body system but integrates the eight individual injectors and throttle bodies. The best part of the EZ-EFI 2.0 system is its self-learning capability. You set the parameters with idle, cruise, and WOT air/fuel ratios and the system uses feedback from the oxygen sensor in the exhaust to maintain these inputs at all time. It operates as simply as its description. With the EFI system assembled and the Vintage Air Front Runner accessory drive bolted down, it was time to put the 427 on the dyno and test its mettle.
With the engine on the dyno, Shaver's dyno operator Ron MacAskill set the WOT air/fuel ratio to 12.8:1 and integrated 30 degrees total timing into the FAST ignition controller and pulled the handle. After several runs up the rpm curve, the Road Tour 427 rewarded us with a solid 534 lb-ft of torque at 3,500 rpm. Had we pulled the engine down to 3,000, it's likely the big-inch LS will make 500 lb-ft of torque. That's enough to get even a big 1959 Impala moving. The power only went up from there with a peak torque of 602 lb-ft at 4,800 rpm and then on to an impressive 622 hp at 6,000 rpm. That's a nice 1,200-rpm power band between peak torque and horsepower and promises to be able to annihilate the tires nearly at will. We can't wait. As we are editing these final words, the 427 is being gently snuggled into its engine compartment at Hot Rods by Dean in Phoenix. The next moves might find our intrepid 1959 moving under power at last.
6. An initial mockup by Shaver engine builder Lee Clapp revealed that the connecting rods required minor clearance on the bottom of the cylinder sleeves. The RHS piston oilers also had to be modified to work with the longer stroke.
7. Pre-assembly includes setting end ring gaps on the 0.043 top and 1.5mm second rings. The oil rings are 3 mm. Conventional wisdom now dictates a slightly wider second ring gap to prevent pressure building underneath the top ring, which can unload it causing leakage.
8. Checking the piston deck height is also crucial to compute the static compression ratio. The Mahle flat-top pistons protrude 0.006 inch out of the top of the block, which is fairly typical for most LS engines when using thick MLS gaskets.
9. Once the block was finish honed to fit the Mahle pistons and subjected to a good cleaning, Clapp dropped the crank in for the first of several test-fits. Bearing clearances, crank endplay, rod side clearances, and a dozen other critical dimensions all have to be checked before final assembly. This time-consuming effort is why it there are no shortcuts to a professional build.
10. After checking wrist pin clearance (0.0015 inch is a good number), Clapp pushed the round C-clips in place. This is best done only after the pre-assembly work is complete in case minor modifications are required.