| IGNITION |
| ECM |
GM LS7 |
| Tuning Software |
HP Tuners VCM Suite |
| Coils |
GM LS1 Coil-on-Plug |
| Wires |
MSD 8.5mm Superconductor |
| Plugs |
NGK TR-6 |
| Total Timing |
28-deg |
| EXHAUST |
| Headers |
Kooks |
| Primary tube diameter |
1.875-in to 2-in stepped |
| Collector size |
3-in |
Dyno Testing
Assembly And Configuration Changes
All short-block machining and assembly work was completed by experienced technicians at Sunset Racecraft in Lubbock, Texas. Once the short-block is completed, it is normally transported across town to Texas Speed where the ancillary short- and long-block assembly and order fulfillment occurs. Since Sunset Racecraft is equipped with a Dynamic Test Systems, Inc. (DTS) model 4000G engine dyno, Texas Speed performed its portion of the labor at Sunset Racecraft, along with all configuration changes of the LSX454 while in the dyno cell.
Dyno Test Procedures
HP Tuners VCM Suite was used to tune the LS7 computer that utilized a Superior Wiring Harness for testing. Each configuration shown in a dyno graph was "tuned" to optimize the specific combination on the dyno. No LS-series knock sensors were employed in the testing, as all dyno runs were recorded and analyzed with HP Tuners before additional changes were made to optimize the combination. In general, timing was locked at 28-degrees and the targeted air-fuel ratio was 12.8-13.0.
Though a specific component achieved a dyno recorded gain, it should be noted that the object of the testing was not to document a specific component, but rather to systematically increase the amount of air flowing through the engine to allow it to produce more power and torque. The test order for each component provides an empirical data point as to how the component itself will perform, but changing the order of the component testing would most certainly change the individual results.
VP 101-octane unleaded was utilized in the cell (TSP says 93-octane would work just as well), fed to the engine via the shop's Aeromotive fuel pump, and regulated to 58 psi. Please note that the brake-specific fuel curve (BSFC) shown on the dyno graphs is inaccurate, as it is measuring the amount of fuel moved through the dyno's fuel cell rather than through the engine. In order to ensure consistency in the test results, the various combinations were pulled after the engine had recorded 165 degrees on the test cell's DTS model S-1007M engine cooling system. The DTS specific cooling system provides for the cooling requirements of the engine, and no engine accessory belts were required, since a Meziere electric water pump was utilized.
Once the engine reached the proper temperature, the dyno operator took it to 3,800 rpm and then applied a dyno load. Once loaded, the engine was slowly brought up to 3,000 rpm and then pulled until the specified redline. Standardized SAE calculations were used to correct the horsepower and torque to industry standards. Reference temperatures for SAE calculations are 77 degrees Fahrenheit and a barometric pressure of 29.23 inches of mercury.
Conclusion
For enthusiasts looking for maximum performance, the LSX block is a terrific value, and the stability of the bores allows for any number of power-adders that can take the output from 1,000 to more than 2,500 horsepower. Although drag-race applications are becoming more prolific, the allure of a 750-horse engine that has an acceptable idle with tremendous power puts the Texas-Speed LSX 440 and 454 combinations high on our list for bang for the buck. A complete short-block retails for $5,895 (PN 24-454LSX or 24-440-LS7) while a long-block retails at $9,899 (PN, 25-454LSXLB or 25-440LS7LB). For enthusiasts who need an intake, fuel system components, and headers, the complete package runs $12,107.
The camshaft is retained with...
The camshaft is retained with an included LSX front thrust plate that was designed specifically for the block and the revised-priority oiling system to provide additional oil between the camshaft, its thrust plate, and the cam gear. Six button-head 8mmx1.25-inch cam-plate bolts are removed with a 5mm hex wrench, which then provides the builder with full access to the camshaft.
A custom Comp Cams hydraulic...
A custom Comp Cams hydraulic roller with 262/270 duration at 0.050 with 0.686/0.658 lift on a 114 LSA should really wake up the engine. After the new camshaft is lubricated with Permatex Ultra Slick Engine Assembly Lube, it is carefully guided into position and the process of buttoning up the engine commences.
The final test really validated...
The final test really validated how an aggressive cam and the porting of the PRC LS7 heads worked together to make tremendous power-a staggering 750.7 hp at 7,000 rpm with 624.8 lb-ft of torque registered at 5,600 rpm. Power increased by 32.5 hp at 6,400 rpm with torque posting modest gains of 3.7 lb-ft. At 5,200 rpm and above, the revised camshaft split that increases intake duration, and just as importantly pushes more exhaust, really paid off. LS7's are known for their marginal exhaust characteristics, and even in ported form the use of more duration on the exhaust pays dividends. For the power junkies searching for an engine that will idle and still make back-crushing torque and eye socket extending power, look no further.