The long stroke required minor machining of the stock C6 oil pan for windage tray clearance. As is the case with most stroker cranks, it was also necessary to lower the windage tray using head bolt washers. Prior to assembly, the new Federal Mogul oil pump was lightly ported to improve flow.
The final touch was a new custom Comp cam spec'ed out by Engine Power Systems. The hydraulic roller featured 0.660 lift using the factory 1.8-ratio LS7 rockers, along with a 251/266-degree duration split. It was installed using a new set of LS7 hydraulic short-travel roller lifters from Comp. The short-travel lifters make the cam act more like a solid lifter. It won't bleed down at high rpm.
The cylinder heads chosen for this stroker might surprise a few LS enthusiasts. Rather than the high-zoot LS7 or only slightly less zooty LS3 heads, Brian chose a set of Trick Flow GenX 245 cathedral-port heads. Some might dismiss the cathedral-port design in favor of the higher-flowing rectangular ports offered by the LS3 or LS7, but these Trick Flow GenX 245 heads delivered not only some serious peak and average flow numbers (see flow data), but offered impressive torque gains lower in the rev range compared to the LS3 (or LS7 heads). The 245 GenX heads were given the optional nitrous exhaust port work, along with a 50-degree valve job to keep over-scavenging of the cylinders in check during overlap.
Exhaust modifications also included a reduction in valve size from 1.60 inches down to 1.58 inches. Thanks to the precision CNC porting and a 2.100-inch intake valve, the intake ports on the 245 GenX heads flowed 353 cfm at 0.600 lift, while the exhaust ports checked in at 278 cfm.
Minor modifications to the heads included repositioning the rocker stud holes to accept the 1.8-ratio LS7 (exhaust) rockers. Brian also stepped up to the .375-inch diameter chrome-moly pushrods from Comp for this stroker. The Trick Flow Specialty heads were secured to the short-block using 1/2-inch ARP head studs and custom (.066) Cometic MLS gaskets designed for the 4.125 bore.
The finishing touches on the 454 were a new FAST LSXR intake and matching 102mm throttle body. Though impressive right out of the box on a variety of different engine combinations, the FAST intake was disassembled and port-matched to the GenX 245 heads. It is this attention to detail that separates this stroker buildup from your average LS motor. All testing was run with a FAST XFI management system and billet aluminum fuel rail with factory LS3 injectors.
To ensure adequate fuel delivery, the static fuel pressure was pumped up to 65 psi. The 454 stroker also received a Meziere electric water pump, a new set of Denso Irridium spark plugs (IQ27s) and a set of 1-7/8-inch stainless steel headers from American Racing. In truth, the motor would likely make even more peak power with larger 2-inch primaries, but chassis fitment becomes an issue above 1 7/8 inches.
The 454 was treated to a pair of computer-controlled break-in procedures before running in anger. After the break-in and preliminary tuning, the oil was changed to synthetic 5W-30 from Lucas. With 29 degrees of total timing and the air/fuel hovering near 13.0:1, the 454 pumped out peak numbers of 704 hp at 6,400 rpm and 630 lb-ft at 5,300 rpm.
In addition to reaching the magic number, this stroker offered an exceptionally broad torque curve, bettering 600 lb-ft of torque from 4,100 rpm to 6,100 rpm. Torque production never dipped below 570 lb-ft anywhere in the tested rev range. This is is one serious street motor and proof positive that you can make these LS combinations really thump on pump.