Racing Engine Design 370 Gen Iii Chevrolet Ls Engine Completed Engine

Racing Engine Design 370 Gen III Chevrolet LS Engine - Budget Bombshells

These Guys Bent The Dyno Without Breaking The Bank-And Did It With A GM LS Mill.

From the February, 2010 issue of Popular Hot Rodding

By Daryl White

Photography by Robert McGaffin

When the Gen III Chevy engine exploded on the scene just over 10 years ago, it seemed that it would take forever for the everyman to afford one of these technological marvels. And back then, if "Joe the plumber" got his hands on a takeout from a salvage yard it would require a computer genius, a cutting torch, a second mortgage, and a good divorce attorney to get one of the LS powerplants hopped up and in your ride. Those days, my friend, are over.

Today, you can buy a complete Gen III core for about the same as a good virgin 350 four-bolt main block, and get it up and running in your hot rod for next to nothing. And thanks to the hard work of engineers at GMPP and MSD, the parts are now readily available to get that high-tech piece of metal making big power with minimal headaches. You can bolt on a distributor and carburetor and spend your nights cruising instead of poring over ECU wiring diagrams or installing a $1,500 high-pressure fuel system. Just how easy is it to make power? Bret Bowers and his team from Racing Engine Design recently built a 370-cube LS for the 2009 Jegs Engine Masters Challenge that made an impressive 579 horses for an even more impressive $6,600.

Our tantalizing tale of Bowers' budget bombshell begins with a journey back in time to when our troops were being welcomed back from Desert Storm (thank goodness that's all over), the Soviet Union imploded, and both Magic Johnson and Freddie Mercury announced that they had AIDS (but not together). That year was 1991, and Tom Stephens, executive director of GM Powertrain, was tasked with laying down the brushstrokes for a completely new multipurpose pushrod V-8. He took advantage of all of GM's resources, most specifically the team he had working with him as well as numerous others contributing to the cause. Weighing a solid 100 pounds lighter than its predecessor, using new casting technologies, Finite Element Analysis, and incredibly powerful cylinder heads designed by the legendary brothers Ron and Ken Sperry, the Gen III 5.7 engine was dubbed the LS1 and finally took life in the '97 Corvette. The Gen III family quickly grew beyond its 5.7L matriarch and expanded to include 4.8-, 5.3-, and 6.0-liter variants as well. Though all are kin and share the Gen III label, only the 5.7L version is designated the LS1 by GM. Somehow as it evolved, the other cube sizes just seemed to inherit the LS designation. Who would have thought that with the overhead cam platforms becoming so popular and efficient GM could create a lowbrow pushrod engine that could not only compete with, but blow away the OHC engines of the time?

Once that new engine grew out of its toddler phase and took longer strides in the high-performance world, it was only a matter of time before the aftermarket was able to fully realize its potential. Coincidentally, core and takeout prices for the LS were dropping out of the stratosphere and into a more breathable atmosphere. The timing couldn't have been more perfect for Racing Engine Design to undertake this project.

Talking with Bowers at his Fort Campbell, Colorado-based engine shop, he says that the modified Gen III business is now booming and he wanted to showcase what could be done to make good, reliable power with a minimum budget. "I looked at it from a budget aspect, and I looked at the factory parts, the crankshaft and the counterweights and how GM put that engine together. I thought it was way more than adequate to make the power we were going to make. I thought if guys bought a used 6.0-liter, and they wanted to put different heads on it and bore it and they wanted an iron block, that it would be a great deal." Sourcing an iron 6.0L block as a core was easy, since they are turning up at salvage yards and eBay sales by the dozen. Bowers says that with the factory six-bolt main caps, the block would easily handle around 1,000 well-tuned horses, and with aftermarket steel main caps, could possibly handle 1,500. Those are big numbers for a stock block. With a target of around 600 hp, he just kept the factory caps and fasteners, though as they are torque-to-yield, new bolts were a must. Once the caps were mocked up in place and bearing clearance was checked, he found the oil gap in spec but on the tight side, so he just bumped it with a few strokes of his align hone, reducing the bearing crush slightly and opening up the oil clearance to just over two thousandths.

Melling's M-Select pump is generally regarded as the pump of choice for LS engines, and that was used on this low-octane 370. Two pump options are available for the Gen III engines. The 10295 pump is a stock-volume pump with 10 percent more pressure than an OE pump, and the 10296 pump offers an 18 percent increase in volume over the stock pump. Both feature hard anodized housings, steel gears, and a phosphate-coated iron rear cover for reduced wear. During the Gen III oiling system development, GM engineers had a tough time with the original oil pan designs because they were so shallow and close to the crank. Fortunately, with the resulting "batwing" pan and the truck pan, the majority of oiling issues were handled. The only major oiling system change that GM made was to enlarge the oil passage crossover at the back of the block from the '99 model year forward. Bowers says the oiling system on his 6.0L block was more than adequate for the task, so no other modifications were necessary. He tells PHR: "I didn't change passageways or restrictions, or anything like that. We used the stock truck oil pan, pickup, and windage tray."

Though some guys jump straight to a forged crankshaft for a high-performance buildup, the RED crew said that for the power levels they were running, a stock cast crank would do the trick just fine. With rolled fillets and lightening holes drilled to help move crankcase pressure between the cylinders, they have been known to hold well over 600 hp. The crankshafts used in Gen III Chevys were all cast iron but there were some minor differences. The 4.8 engine used a 3.268-inch arm but 5.3/5.7/6.0 engines all used the same 3.622-inch stroke. With rebalancing, all of those are interchangeable, similar to dropping a 305 crank in an early 350. The only major variance in cranks is that the 216-casting cranks used in automatic '99-00s had a rear flange that was about .860-inch longer than the more common 215-casting cranks. That could pose a problem for an engine/tranny swap. The factory cast-iron 216-casting crankshaft for this buildup was deburred and balanced, but was otherwise untouched.

Bolted to the factory crank was a set of Eagle lightweight connecting rods that came equipped with ARP's famous 2000 Series rod bolts. The advanced metal in the 2000 bolts is significantly stronger than the more common 8740 material, and not as susceptible to moisture and oxidation issues as the L19 bolts. With rod clearance at just under two thou, the guys had no problems with their recycled OEM rod bearings.

Mahle has been supplying high-end racers with top-notch pistons for years and since introducing their Power Pak piston/ring packages a few years back at a budget price, they have really taken over in the world of moderately priced street/strip engines. A low-tension metric ring package and short skirts coated with an anti-friction Teflon-based coating were big factors in Bowers' choice of Mahle for their pistons. They were used out of the box, save for some minor valve notch clearancing that was required for the big LS7 intake valves.

Did we not mention the LS7 heads? Bowers picked them up as bare castings on eBay for just five Bennies. Saving enough from not buying the heads complete, he was able to score a set of big-block sized 2.200-inch Manley intake valves and 1.540-inch exhaust valves to use in the heads. Manley was also the source for the polished Nextek springs, retainers, and locks, keeping those valves in check.

LS7 heads were, of course, available on the Z06 Corvette, and came with giganto CNC-ported runners, Titanium valves, and flow numbers that make 18-degree small-block guys want to throw rocks at their high-dollar engines. Since the RED engine was designed to make big average torque and horsepower numbers from 3,000 all the way to 7,000 rpm, they decided to shrink the runners down from around 250 to 238cc with carefully placed epoxy. Final hand blending of the runners was the only other modification to the heads. They felt that the combustion chamber design was perfect to begin with, so they never even touched them. Fel-Pro MLS head gaskets and ARP head bolts joined the heads to the short-block.

Acting as a mechanical ECM for the engine was a custom Bullet solid-roller cam with aggressive lobes urging the COMP Cams roller lifters. Thanks to the factory location of the runners and offset rocker arms, they were able to use 3/8-inch diameter pushrods to minimize harmonics and maximize ultimate lift. Surprisingly, the Harland Sharp roller rockers fit under a set of stock valve covers with just a touch of clearancing on the tips. With the correct valvetrain geometry set, the crew didn't have any issues on the top end.

A quick search for GMPP PN 88958679 produced a number of retailers offering the front drive distributor conversion kit for the LS engines. The kit not only includes the timing cover itself but a fuel pump eccentric for use with a mechanical fuel pump, a distributor drive gear, spacers, bolts, and a crankshaft seal. With the conversion kit in place, all that it takes is a small-block Ford distributor (cough, cough), like the MSD Pro Billet dizzy that Bowers scrounged to get fire in the hole. Feeding the flame was an MSD Digital 7 ignition box and HVC II coil.

With compression and ignition taken care of, the final element of the internal combustion triangle was fuel. Shell V-Power 91-octane pump gas entered the Quick Fuel 4150 carb and thanks to our friend Bernoulli, was drawn through the main jets, emulsified with air pulled through the air bleeds, and atomized as it exited the annular boosters. The 1,050-cfm unit uses a three-circuit design that allowed Bowers and teammate Jason Gonzalez to tailor their fuel curve to their liking both at their mile-high shop, and at the near sea-level conditions of the University of Northwestern Ohio-based Challenge. Since tuning is such a big deal in getting the most out of a combination like this, they spent quite a bit of time dialing it in at home. "It had a five-hole emulsion bleed in the metering block, and we were blocking the lower two, then we were blocking just one, and we were trying to straighten out the curve on the top side and we got it pretty good."

With the air/fuel mixture perfectly homogenized, it passed through the two-piece intake manifold that is, by itself, a work of mechanical art. The intake was designed by Performance Induction with a large plenum to feed a good-sized engine.

To make it easier to work with it can be split in two for porting, then joined back together with an O-ring seal. Bowers just did a little minor touch-up and port matching to the heads to get the fit right, but the intake was otherwise untouched.

A turn of the starter and the machinery came to life, ready to embarrass some bucks-up entries that cost two to three times what Bowers' little budget buster set him back. The dyno operator made three back-to-back pulls like he was shifting a Lenco, and as a testament to the efficiency of the engine, it varied by a mere one average horsepower and lb-ft in all three pulls. The torque curve looked like a giant Southwestern mesa. Through a pair of Magnaflow mufflers and 13 feet of pipe, the exhaust note sang crisp and clear. Best of all, with less than $7Gs in his engine, Bret and his crew were able to travel first class all the way back to Colorado.

BY THE NUMBERS
RACING ENGINE DESIGN 370 GEN III CHEVY
Bore:	4.030-inch
Stroke:	3.622-inch
Displacement:	370 actual cubic inches
Compression ratio:	11.34:1
Camshaft:	Bullet solid roller
Cam duration:	247/247 degrees
	at .050-inch tappet rise
Valve lift:	.810/.810-inch
Rocker ratio:	Harland Sharp
	1.8 intake / 1.8 exhaust ratio
Top ring:	1.5mm
Second ring:	1.5mm
Oil ring:	3mm
Piston:	Mahle flat-top
Block:	OEM cast-iron
Crankshaft:	OEM cast-iron
Rods:	Eagle 6.125 H-beam
Cylinder head:	OEM LS7
Intake valve diameter:	2.20-inch
Exhaust valve diameter:	1.54-inch
Intake manifold:	Performance Induction
Carburetor:	Quick Fuel 1050 4150 style
Header:	Pacesetter 13/4-inch primary
Ignition:	MSD 7

DYNO DATA
Best Qualifying Pull
RPM	TQ	HP
3,000	407	232
3,100	410	242
3,200	407	248
3,300	402	252
3,400	398	257
3,500	392	261
3,600	388	266
3,700	386	272
3,800	388	281
3,900	396	296
4,000	414	316
4,100	432	337
4,200	447	358
4,300	460	377
4,400	470	394
4,500	479	410
4,600	487	426
4,700	490	439
4,800	493	451
4,900	499	465
5,000	500	476
5,100	498	484
5,200	499	494
5,300	499	504
5,400	498	512
5,500	498	521
5,600	497	530
5,700	495	537
5,800	492	544
5,900	490	551
6,000	489	559
6,100	487	565
6,200	483	570
6,300	480	576
6,400	474	578
6,500	468	579
6,600	461	579
6,700	452	577
6,800	446	577
6,900	440	578
7,000	433	578

WHERE THE MONEY WENT
6.0L short-block core	$250
Eagle connecting rods	$429.99
Mahle pistons	$479.99
COMP Cams solid roller lifters	$489.99
Fel-Pro MLS head gaskets	$188.84
Engine Pro timing chain set	$75.42
Melling oil pump	$65
ARP head bolt kit	$146.88
Engine Pro 3/8x8.1-inch pushrods	$116.48
Fel-Pro timing cover gasket	$48.44
K&N oil filter	$13.99
Intake manifold	$1,106.23
Distributor drive kit	$456.98
Harland Sharp roller rockers	$598.88
Manley springs, retainers, locks	$485.23
Total Seal piston rings	$259.38
Bullet camshaft	$359.99
Manley race-series valves	$379.98
LS7 heads (used), eBay	$500
Valve covers (used)	$30
MSD distributor (used)	$125
Total:	$6,606.69