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  • 2004 GMC Sierra Engine Upgrades - 358 RWHP 4.8L With Bolt-Ons

2004 GMC Sierra Engine Upgrades - 358 RWHP 4.8L With Bolt-Ons

Project Novakane Part V: 294ci + Go-Fast Goodies = 358 RWHP

Dan Ward
Dec 1, 2010
Photographers: Dan Ward, Bob Ryder, Harley Camilleri
Part V It's as addicting as Rock Band, Facebook, and texting, combined. Horsepower-once it gets into your veins, there is no turning back. After doing several basic modifications (including Banks air intake, headers, exhaust, and programmer) to our '04 GMC Sierra, dubbed Novakane, and seeing immediate results, the desire to go faster never relinquished its stronghold. Knowing our tired 4.8L, with 150,000 miles on the odometer, wouldn't hold up much longer to the extreme abuse we were putting it through, we opted to make the most of its last days by bolting on the same parts you may be considering for your truck. Rather than pull the engine, we left it in place, and we also didn't remove the factory aluminum heads thinking the average Joe wouldn't want to pull them either. For the shade tree mechanic, all of these installs could be done in your garage and depending on your engine's history and modifications, you could expect similar horsepower increases.
Photo 2/71   |   2004 GMC Sierra Engine Upgrades project Novakane
Nitrous. That word either brings curiosity or a big smile to your face. There are many myths about nitrous, but the fact is, if you install it correctly on a healthy engine, it will produce more horsepower per dollar than any other mod. We bolted on a NOS drive-by-wire wet kit from Holley and were amazed at how easy each part was to install. The kit included everything we needed, looked great once installed, and performed beyond expectations.
Electric fans are finally being used on most new 1/2-ton trucks because the manufacturers realized what we've known all along, the initial cost is quickly an afterthought once more power, better cooling, and better mileage is experienced. Using an application-specific dual 15-inch fan kit from Flex-a-Lite, the 4.8L quickly responded to the easy install.
With our little V-8 making more power than ever, we didn't call it a day, rather we ordered a full complement of parts from Comp Cams and FAST. The UPS driver delivered a new Tri-Power Xtreme cam, FAST LSXRT 102mm intake manifold, billet fuel rails, also from FAST, and the necessary installation parts (valve springs, keepers, seats, locks, seals, and trunnion bearings). To make our truck run its best, we called Sean, over at SoCal Tuning, to make a couple of pulls on Superior Automotive's dyno and dial in our ECU. The end result showed a 294ci engine producing 297 hp at the tire before the nitrous, and 346 with the spray.
Helping get our LS engine get over the 300 naturally-aspirated rwhp mark, we bolted on an ASP Racing underdrive pulley set and saw the dyno read 306 rwhp. With nitrous activated, the 4.8L produced an astounding 361 lb-ft of torque and a respectable 301 lb-ft without spraying the go-juice. Gentlemen, start your engines.
Read on, as we show you how, with several vital upgrades, we made our Sierra a tire-roasting kick in the pants.
There is a great deal going on in this story, and we wanted to show you the highlights. This is by no means a step-by-step or how-to story as it is more an overview of what and how we made our truck go faster. With that said, these parts shouldn't be overlooked as just go-fast, gearhead eye-candy. Each part installed steadily increased horsepower and the culmination of each part really turned our little 4.8L into a respectable street prowler. There aren't too many naturally aspirated 294ci V-8s producing more than 300 rwhp and we're proud to say this one does. Admittedly, 150,000 miles is a little late in the game to start squeezing horsepower out of a work truck, but it handled everything we threw at it without a hiccup. Our only areas of concern were the necessary fuel line fittings, hoses, and adapters that were required to make the new fuel rails work with the factory high-pressure fuel line. Also, the front steam line had to be replaced with a dealer part because of intake clearance. Lastly, we needed a shop press to install the trunnion bearing upgrade for our factory rocker arms and didn't realize it until everything was torn down. Thankfully, each challenge wasn't too difficult to overcome, thanks to Sweet Performance Products fuel hoses, a 6.0L steam line from a GTO, and the purchase of a press. Now that you know what we know, there shouldn't be any surprises if you follow our lead. We're happy to report our only shortcoming was following the truck repair manual's new valve stem seal instructions. We did what it recommended and slid them down the valve stem within a .712 inch tolerance rather than using a 9mm deep-well socket and tapping them all the way down the valve stem (which is what our common sense told us to do, but we didn't listen). Not every valve stem seal seated properly and after sitting for a couple of days, cylinders 5 and 6 were filled with half a quart of oil-bummer. Our engine was hydrolocked and rather than take it back apart, we're going to swap in a GM Performance Parts crate engine. Check out next month where we'll unveil the future for Project Novakane.
Time Spent Working: A combined 26 hours total
Degree Of Difficulty: A competent shade tree mechanic could handle it
Tools Needed:
Inch-pound and foot-pound torque wrenches, 8, 10, 12, 13, 15, and 24mm sockets, pliers, snap-ring pliers, a shop press (or large vise), valvespring tool 17/16-inch wrench, 5/16-inch nutdriver, 7mm Allen socket, T-20 Torx bit, 3/8-inch drill bit, impact gun, drain pan
Parts Used:
ASP Racing underdrive pulley kit 549920 $249.95
COMP Cams Tri-Power Xtreme camshaft 54-530-11 $396.95
COMP Cams valve springs 26915-16 $187.95
COMP Cams trunnion bearing upgrade kit 13702 $134.75
COMP Cams valve spring keepers 774-16 $51.95
COMP Cams valve seats 4705-16 $33.95
COMP Cams valve locks 623-16 $30.95
COMP Cams valve stem seals 511-16 $25.25
FAST LSXRT 102mm intake manifold 146602 $994.95
FAST billet fuel rails 146028-kit $187.25
FAST billet throttle-body adapter plate 146029 $34.95
Flex-A-Lite dual electric fans for GM trucks 282 $549.95
Nitrous bottle fill-up $4.00 a pound $40.00
NOS Universal Drive-By-Wire wet nitrous kit 05135NOS $704.95
Pro Precision Billet single 10-lb bottle bracket $199.99
Sweet Performance assorted fuel hoses/fittings $220.00
Total: $4,043.74
(All prices from Summit Racing and ASP Racing and do not include tax, shipping, or installation)


Fife, WA 98424
Comp Cams
Memphis, TN 38118
Summit Racing
Akron, OH
Auto Specialties Performance (ASP Racing)
Stafford, TX 77477
SoCal Tuning & Performance
Anaheim, CA 92801
Bowling Green, KY 42101
Superior Automotive
Anaheim, CA 92801
Pro Precision Billet
Downey, CA 90239
Sweet Performance
Placentia, CA 92870



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