October '17

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OCTOBER 2017 PRECISION ENGINE 3 PRECISION ENGINE Motown II LS Build Part 4 Final assembly & dyno numbers. EDITOR'S NOTE: The following is the fourth and final installment in a series documenting the build of an LS engine from a Motown II block. See Part 1 in the January 2017 issue of THE SHOP magazine, Part 2 in the April 2017 issue of THE SHOP and Part 3 in the July 2017 issue of THE SHOP. T his article completes the assembly infor- mation of our small-block Chevy/LS hybrid build, along with our dyno results. We've built a number of LS-platform engines over the past few years in varying displacements and overall designs. In previous installments documenting this build, we went over the block background, block machining, painting the block, cam bearings, camshaft, crank and rods, rings, timing, the oil pump, cylinder heads, Build, text and photos by Mike Mavrigian lifters, rockers, pushrods, the intake mani- fold and valve covers. The build produced a respectable 641 hp at 6,300 rpm, and 555.7 foot-pounds of torque at 5,200 rpm. While our time on the dyno was rather limited, we suspect that further tweaking with a few changes would likely boost by another 20 hp or so with a change from our Trick Flow cathedral-port LS heads to LS3-style Trick Flow heads along with a taller intake plenum—either with a taller intake manifold or the addi- tion of a 1-inch carb spacer. However, our experience has been that the cathedral port heads offer slightly higher torque, which was our reason for choosing them for a street performance application. The COMP Cams' three-piece timing cover features a base, top half and lower half. An inspection hole in the lower half allows easy cam gear thrust checking.

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