LT1 Engine Build - Small-Block 2.0

Golen Engine Service Makes the LT1 Its Performance Platform

John Nelson Oct 6, 2006 0 Comment(s)

QUICK NOTES

What's on Tap
We get the inside scoop on Golen's LT1 creations.

Combos
A 440-horse 383 stroker, and its 480-horse sibling

Price
$5,999 for the 440, $6,899 for the 480

Alas, the LT1-you were here, then you were gone, and we hardly got to know you. The second-generation small-block Chevy stuck around for a mere six model years before being supplanted by the mighty LS1. This short life span might make it easy for some to regard the LT1 as a mere footnote in the pages of small-block history. But let's look at that lore. When the Gen II powerplant debuted in the '92 Corvette, it came rated at 300 hp-a stunning 45-pony increase over the best factory TPI mill. The engine's finest iteration, the LT4, came packin' 330 hp. Opti-Spark notwithstanding, the LT1 delivered the goods in some great-performing cars, and it can still pack quite a punch. Just ask Chad Golen, proprietor of Golen Engine Service (GES).

Although his outfit builds a varied array of performance motors, GES is arguably best known for its high-performance LT1s. "A lot of people push them aside," Golen tells us. "But they work well and are very reliable." More than a few people must agree, since GES buys its cores in lots of 100. Ninety-nine percent of the engines he builds, Golen tells us, go into vehicles that originally came with LT1s. "They weren't out long enough for much transplanting," he adds. But that's OK with him, since there's a steady supply of Corvette, Camaro, Impala SS, and Caprice owners looking for more power.

We asked Golen about the pros and cons of making power with the LT1. The disadvantage is...surprise, the much-maligned Opti-Spark ignition system. "When it works, it works well," he tells us, asserting that a few bad apples have created a bad reputation. When it comes to advantages, it turns out the list is much longer, the biggest plus being the Gen II's reverse-flow cooling system. "The coolant enters the cylinder head first," Golen explains. "This allows the head to stay cooler, and us to run higher compression." In concrete terms, this means that GES builds stroker LT1s that run 11.5:1 compression while retaining their ability to use pump gas and pass emissions. "You need to use the smog equipment," Golen cautions. "And computer tuning is mandatory." But with those provisos, GES says its engines are "direct bolt-ins" for any car that came with an LT1.

When it comes to the rest of the engine, Golen tells us that "a good chunk" is the same as a traditional small-block. Accordingly, making power with the LT1 follows traditional methods. GES goes to great lengths to create a bulletproof bottom end, installing aftermarket four-bolt mains and forged internals in each engine, and addressing this particular engine's reputation for lunching rod bearings. "Our customers should expect quality," Golen declares, and backs up the talk with an extensive warranty. As is almost always the case, however, the road to horsepower goes through the cam, heads, and intake manifold. "The factory cylinder head is a really good base," Golen observes. "It flows good with fuel, and with porting it will support up to 530 hp." Ditto the factory intake manifold. "It's just a very good design," says Golen. Again, with porting, power levels approaching 530 hp are supported.

So as it turns out, the bottom line when it comes to building a powerful LT1 is much the same as building any other powerful small-block. On the other hand, some unique GM design features give the Gen II small-block some power-enhancing advantages. Keep reading for the real inside story.

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At 11.5:1 compression, you can use pump fuel and pass emissions.
-Chad Golen

Golen Engine Service buys LT1 blocks in lots of 100, ensuring that it always has powerplants on hand. Each core is thermally cleaned, blasted with stainless steel shot, and inspected for cracks by MPI process. Those that pass the test are then decked, bored, and honed with torque plates.

Both the 440- and 480-horse stroker motors receive an Eagle cast-steel crank, providing a substantial step up in strength from the stock cast-iron piece. The new 'shaft is internally balanced, meaning the LT1 original externally balanced flywheel or flexplate can't be used.

In their day, LT1s were known to occasionally spin a rod bearing. According to Golen, the combo of 0.0015- to 0.0018-inch factory bearing clearance and 5W-30 OEM-specified oil wasn't up to forced-induction apps or other hard usage. GES opens up the clearance to 0.0025-0.0030 and specifies 20W-50 Valvoline oil.

"The stock two-bolt caps are weak," says Chad Golen. Therefore, each LT1 stroker GES builds is fitted with four-bolt main caps and ARP main studs. The main line is the bored and honed for exact straightness before the crank is installed. Note the clearancing work done to accommodate the longer stroker-crank throws.

The remainder of GES' stroker LT1 short-block is filled with Scat 4340 forged rods, full-floating SRP pistons wearing Speed Pro rings, and a Comp Cams hydraulic roller outfit, complete with lifters and pushrods. The timing chain is an LT4 roller setup, made by Cloyes for GM.

Once given a "proper" porting treatment, Golen figures that the factory LT1 head is good for applications that make up to 530 hp. GES starts the process by replacing the stock 1.94/ 1.50 valve pair with a slightly larger 2.00/1.56 combo. Golen assures us that it's enough to make a difference.

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