While it didn’t make major headlines in the marine press, Mercury Racing’s introduction of an LS7-based crate engine at the Specialty Equipment Market Association Show earlier this month rates as significant news from the Fond du Lac, Wis., high-performance marine engine builder. The engine features the company’s new 32-Valve DOHC SB4 cylinder head and valve train.
Mercury Racing-built LS7 crate engines were in several vehicles during the recent SEMA show (click image to enlarge).
Designed and developed to integrate with General Motors LS series hardware, the aluminum four-valve head and dual overhead camshaft valve train provides improved performance and durability versus a standard two-valve design, according to a press release from the Mercury Racing. The head design adapts the company’s proven high-performance valve train to the robust, small block LS engine family.
According to the release, benefits of the DOHC four-valve design versus the typical LS pushrod layout include:
• Improved intake and exhaust flow for improved performance
• Enhanced port flow enables increased horsepower
• Higher engine rev limit for increased horsepower
• Valve train durability due to reduced mass and lower stresses
• Improved drivability due to milder camshaft timing at comparable horsepower levels
This is the third year Mercury Racing has exhibited at the SEMA event. Two years ago, the company made a splash at the SEMA show with a crate version of its QC4v 1,650-hp engine installed in an Ultima GTR Super Car—and that vehicle-and-engine combo was on display again this year at the Mercury Racing booth. Last year, the company showcased its in-house-designed four-valve heads on an LS engine.
The Mercury Racing-built LS7 engine was displayed in several vehicles including a custom street rod from Slick’s Garage of Palmetto, Fla., and a 1970 Plymouth Barracuda built by Salvaggio Automotive Design of Port Washington, Wis.