This engine build coverage could literally be any one of our trips to the machine shop. You go in, talk to the builder about plans for your engine, and what you want to do. You drop off the engine, some magic happens, and then badda-bing, you have an engine.
Well, for Ken Kurtz, it wasn't quite that simple. He had very specific needs for his engine. He thoroughly expected to beat the living crap out of his LSX and needed big power to make it all happen. He is a NASA racing series champion, and needed a seriously stout motor to shore up yet another championship. He went to TPiS of Chaska, Minnesota to do just that. They built the engine that powered his third-gen Pontiac Firebird to his 4th NASA USTC-GT championship. Hang tight, because we are going to reveal how it was all done!
We have to warn you, however, before you set off building your own road-racing monster; these engines don't come cheap, and things like the dry-sump system will set you back many pretty pennies. But the old age answer to the age old question of "How fast do you want to go?" is still "How much money you got," and that very much holds true - espessially in this case. LS-series powerplants have gotten pretty inexpensive these days, but despite their reliability and price point, they are still machines and pushed hard enough anything will give out.
Finally, before we jump into the guts of the build, we've heard the criticisms of previous magazine engine builds. Trust us, we've heard the "oh, it's just a dyno queen," and "that thing will never stay together." We assure you that this engine has been run at speed and at full throttle for hours at a time. This is a winning combination.
So let's jump in and see what it takes to make 743 horsepower and 581 lb-ft of torque, and live long enough to bring home some major hardware!
1 The TPIS 90mm throttle body takes big gulps of air at WOT.
2 The foundation for Ken’s engine started with a stock GM LS3 6.2L aluminum block. The block will get a slight bore to have a 4.100-inch bore. That combined with the 4.000-inch stroke makes his engine measure in at 422-cubic inches.
3 The crankshaft used here is a Callies Dragon slayer 4340 crank with a 4.000-stroke and Clevite bearings. Just above, you’ll see the custom ground solid roller camshaft with 244/256 .680/.680 and 110LSA specs.
4 A set of 8 coated top and skirts, made by Diamond (PN# 62916), are the choice for this combination. They have a +8cc dome height and a comp height of 1.110.
5 A good build with big power needs a quality connecting rod. They didn’t want to get bent out of shape (pun intended) so they went with a Compstar H-I rod (PN# CSC6125 DS2A2AX).
6 The bottom end needs all the strength it can get. Assembly is pretty straight forward as with any other engine build, torque in proper sequence and double check your work. This engine will have a compression ratio of 13.5:1.
7 The cylinders get a 0.040 bore with this hot mess of an action shot.
8 A new intake manifold had to be custom made, as the stock piece just wasn’t going to cut it. The inlet housing is held in place as the sheetmetal is formed to the correct shape, and welded. The throttle body housing is designed to fit the TPIS 90mm throttle body.
9 A double roller timing chain is a no-brainer. This motor uses a 0411 24X PCM, which allows the TPIS guys to tune a little better with greater ease of the V1 system.
10 The heads is where most peoples money is at. Ken opted for a set of WCC LS3 heads, with a 280cc intake and a 268cc exhaust. These heads flowed 380cfm at 0.700 lift. They utilize 2.200 intake valves and 1.600 exhaust valves. Isky solid-roller lifters combine with Smith Brothers pushrods, and a 1.7-inch COMP Cams rocker tops off the head side of the equation.
11 After the intake was finalized, the guys can mount the fuel injection system, the 60lb Bosch injectors, the stock GM coils, the fuel crossover tube, and the coolant equalizer tubes.
12 This is a serious road race motor, and it demands a serious oiling system. Ken’s engine uses a dry sump system, with an ARE T1 dry sump kit that utilizes the LS2 dry sump pump, and oil pan.
13 Here we have the LS3 ready for dyno testing. Helping the combination breath is a set of America Racing headers with 17⁄8 primaries and a 3-inch collector that let the engine breath liquid hot magma.
14 Hitting the dyno, the engine is massively obscured by the primary oiling tank that is required with all dry sump systems. The engine made a maximum of 743 horsepower and 581 ft-lb of torque. It should be said that most race engines make their big power up high where it really needs it and spends most of its life.