The key to any successful buildup is to follow a basic formula. Step one is to decide on a budget, followed by a realistic power goal for the intended application. By realistic, we mean forget about the four-digit power outputs for your daily driver and instead concentrate on what really matters. In most cases, the budget will determine the eventual power output or at least how you go about getting there.
While a brand-new crate motor might be high on the list, the fact is that a wrecking yard buildup might better fit the budget. An honest evaluation is helpful here to get you going on the right track. With a realistic appraisal of the budget and power goals in mind, it is time to start mapping out the components that will help you achieve your goal. Questions that fall into this category include engine family (big- vs. small-block), displacement and even available octane versus compression ratio. You can't build a motor with 12.5:1 compression and hope to run it on 87 octane. Talk with professionals in the industry to help sort out the components that will best suit your needs.
The final step is the assembly procedure, which may include several mock-ups to rectify any clearance issues. But take your time here and you'll be rewarded with a serious performer that can last a lifetime.
For this particular LS1 buildup, engine owner Brian Tooley set his sights on a power goal of 700 hp. While 700 hp is not terribly difficult with forced induction or nitrous, Brian took the road less traveled and decided that the power would come without the aide of a bottle or blower. This 700hp project was an all-motor effort.
Further increasing the degree of difficulty was the fact that said buildup must also produce the desired power on pump gas, as it would find a home in a daily driver that would see some weekend strip action. Now things were starting to get interesting, but apparently Brian had a plan that involved an engine builder's best friend when it comes to power production: displacement. Small displacement would require excessive rpm to reach the 700hp mark. Knowing that engine speed and reliability (to say nothing of expense) go hand in hand, Brian's decision to increase displacement likely also improved reliability.
Stroker motors are all the rage and for good reason. Packaged inside what once was a combination ranging from 4.8 liters up to 6.2 liters (depending on year and application), it can be a real monster. Using an aftermarket block or the Super Deck system from ERL, it is possible to build an LS combination exceeding 500 ci.
With a more realistic budget at his disposal, Brian chose 454 cubes as the final displacement. This was achieved by combining the 4.125-inch bore of a 7.0L (427) LS7 with a massive 4.250-inch stroker crank. The bore was no problem, as Brian chose to stuff the stroker inside an LS7 aluminum block, which already featured the intended bore size. Gressman Powersports was responsible for honing the block to perfection, along with align honing the mains and drilling and tapping the block to receive larger 1/2-inch ARP head studs.
Minor machining was also necessary on the outboard portion of the bottom of each cylinder bore for rod clearance (with the massive 4.250-inch stroker crank). The final fitment issue involved the clearance between the rod bolt and camshaft. With only 0.020-inch, a few seconds on the grinder produced the desired 0.050.
With the block prepped, it was time for the stroker assembly from Wiseco Pistons. It included a 4.250-inch, 4340 forged-steel crank and matching 6.125-inch, H-beam rods from K1 Technologies. Naturally, the kit featured dedicated pistons from Wiseco.
The 4.125-inch forged Wiseco slugs featured a flat-top design, coated skirts, and generous valve reliefs for additional piston-to-valve clearance. The assembly was installed into the awaiting LS7 block using Clevite main bearings and coated rod bearings from Federal Mogul. Further strengthening the bottom end was a set of ARP main studs for the LS7 block. Compression was 11.8:1 with the heads we used, high for sure, but with injection and the proper tuning, definitely streetable on premium.
1 The good folks over at Gressman Powersports cranked up the Sunnen RMC V40 CNC to precis
2 The Wiseco stroker kit included a 4.250-inch stroker crank from K1 Technologies and mat
3 What Wiseco kit would be complete without a set of forged-aluminum pistons? The 4.125 W
4 Some machining was necessary to install the stroker assembly, including the oil pan to
5 Why trust such an impressive rotating assembly with a stock damper? To put his mind at
6 Knowing that cam choice is critical for any stroker assembly, Brian went to Engine Powe
7 While some may be tempted to top the large-displacement stroker with a set of LS7 or LS
8 These cathedral-port heads offered impressive flow numbers, topping out at 353 cfm at j
9 The exhaust flow was equally impressive at 278 cfm at the same 0.600 lift. Think about