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A Capable Predator- Air Flow Research's Mongoose cylinder heads for LS engines offer plenty of bite

Written By Steve Baur Photography By Kurt Anderson and Courtesy of Air Flow Research For many racers, the winter months are spent rebuilding, modifying, or upgrading their vehicles. Ever the competitor, reigning Street King champion Kurt Anderson pulled his LS-based engine from his 1969 Camaro for a rebuild and an upgrade using Air Flow Research's Mongoose cylinder heads. Anderson's vintage F-body is powered by a 416ci, LS3-based engine built by Wegner Automotive in Markesan, Wisconsin. The 6.2-liter small-block is filled with Mahle pistons and Callies Comp Star connecting rods, along with a long-forgotten crankshaft and custom Bullet camshaft. With Anderson having the engine freshened up every two years or so, he took this past winter's teardown as an opportunity to change things up. AFR pays contingency in the NMCA, and I like to support those companies when I can, Anderson told us. And with several championships under his belt, the Eau Claire, Wisconsin-based Camaro driver is no stranger to the NMCA Winner's Circle where, in addition to the class purse, racers can also collect a good bit of money and prizes by using parts that pay contingency. The small-block LS3 powering Anderson's Camaro was previously equipped with factory LS3 cylinder head castings that had been CNC-ported, and Wegner Automotive made some secret squirrel upgrades to the valves, as well as trunnion upgrades for the stock rocker arms. On top of those heads is a Mast Motorsports two-piece cast intake manifold and a FAST EFI 4500 throttle body that is controlled by a Big Stuff 3 engine management system. With a compression ratio of 13.5:1, the old combination offered a peak horsepower number of 705.5 at 7,200 and 561.6 lb-ft of torque at 5,800 rpm, which is enough to push his championship-winning machine to a best ET of 9.28 at 142.40 mph (previous best was 9.56) at a race weight of 3,050 lbs. Opening the Air Flow Research box revealed the Mongoose LS3 cylinder heads, which feature a rectangle port design that is machined on AFR's 5-axis CNC machine. Intake runner volume checks in at 260cc while the exhaust comes in a 95cc. The heads are CARB-certified and emissions legal for 2007-2016 6.2-liter LS3 engines, too, in case you're looking for an upgrade for your street car. On the engine side of the heads, you'll find 2.165-inch intake/1.600-inch exhaust valves nestled nicely in a 69cc combustion chamber, which Wegner milled down to around 60cc to obtain the desired compression ratio. The engine builder also performed the same secret valve mods to this set of cylinder heads that they did on the stock castings. The LS3 Mongoose cylinder heads require a minimum bore size of 4.000-inch to clear the 2.165 intake/1.600-inch exhaust valves, and they are intended to be used on engine applications up to 454 ci and the heads are available in 4- and 6-bolt per cylinder fitments. In addition to the competition 5-angle valve job, AFR also performs CNC porting on the intake and exhaust runners. Once the newly modified mill was fired up and ran on the Wegner Automotive dyno, it was obvious that the cylinder heads were not only a potentially profitable choice, but also offered an uptick in performance as well. Horsepower rocketed to 759.5 at 6,900 rpm, and torque rose as well to 599.4 lb-ft. at 6,200 rpm. Once back between the fenders of Anderson's Camaro, the AFR-headed engine continued to perform well, picking up three tenths in the quarter-mile, along with 6 more mph. Sources Air Flow Research (661) 257-8124 AutoKraft Race Cars and Restorations (715) 874-5921 Wegner Automotive (920) 394-3557

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