RegisterSearchFAQMemberlistUsergroupsLog in
Reply to topic Page 1 of 1
98 chevy 2500 truck 5.7 vortec build
Author Message
Reply with quote
Post 98 chevy 2500 truck 5.7 vortec build 
I purchased a 98 chevy 2500 with the 5.7 in it that slung a rod through. I would like to stay with the 5.7 vortec but wanting to know what anybody would recommend for performance upgrades, tips and tricks to get the most out of my new motor I will be installing. Just a mild build to get 50-100 more hp. Open to any and all suggestions. And Also tuning this thing after everything is done. TIA

View user's profile Send private message
Reply with quote
Welcome. There is plenty here on making a 5.7L go better. Look for the marine intake sticky thread. The Vortec's main failing is the built-in injectors that won't support much more than what the factory puts into them. There is no aftermarket support for them either, because it's really a crappy system hardware-wise. If you're not afraid of wiring you can use aftermarket parts and install a more standard style injectors to support more power. The best you can get from a Vortec injection setup would be to stroke it to a 383, and run a stock level cam. It would likely get you another 50HP, but can't really support more than that. If you don't mind burning 93 octane, you can boost compression a bit to help make up some power. Supercharger systems use aux injectors to make up for the extra fuel.

For the money you'd be just as well to convert to a 6.0 or a 6.2 from a salvage yard. You'd need to get the computer and wiring harness and may need the throttle pedal and instrument cluster, depending upon how new the donor is.

For tuning, you can try Dyno & Performance in Fort Smith AR. I've never used them but my dad and brother live in that area and say that this are a pretty popular shop for getting dyno tunes done. I've never used them myself though, and neither have they, so I can't comment from direct experience with them.

View user's profile Send private message Send e-mail
Reply with quote
Since you are a 2500 I'm going to assume you are running the HD 4l80e, which is a good thing. Being a 3/4 ton also means that you will have the larger 2-3/4" headpipes connecting the exhaust manifolds to the larger 3/4 ton catalytic converters.

Depending on how much exhaust work you wish to do a set of Hooker Competition series long tube headers with their 16 gauge 1-5/8 primaries and 2-1/2" collectors would work, 2462-hkr black painted for $262-$521. I ran a set of these in ceramic coating (2462-1hkr for ceramic) 2462-2hkr for stainless steel construction-$700, 2462-3hkr-Darkside ceramic coating-$620 and 2462-4hkr for Titanium ceramic coating-$620.
The Hooker 2806-hkr have the 18gauge tubing 1-3/4" primaries(tuned length) and 3" collectors.(2806-1hkr for ceramic coating-$926)(2806-3hkr for Darkside ceramic coating $947) (2806-4hkr get the titanium ceramic coating $917)

On the above headers, if you want to hook up the EGR you will have to add a bung on the drivers side primary tube.
EGR fitting for GM trucks is a standard home plumbing male 5/8" flare fitting (NOT inverted flare fitting).

They were designed for the 1988-1995 TBI™ trucks but will 100% fit the 1996-98 trucks as they have the same physical dimensions.

Pics/thread of 2806-1hkr that James B used.
Some more Hooker info
pics of the AIR, O2 and EGR bungs on James B Tahoe

Thorley also makes an excellent Tri-Y design set of headers for these trucks as well.

I suggest ceramic coating esp. if you get salted roads in Winter. Every year I rusted through a pair of black painted mild steel headers, once I stepped into the ceramic coated headers, I got over 12 years out of them on my daily driver.

Brand new Vortec 350's are $2000 from Summit Racing and Jegs.

The following prices are good as of today,

12681432 $2,185.60 (2 bolt mains-notice the new part number-12681432 supercedes 12530282)

L31 Vortec 350 LD 1/2 ton trucks 3/4 ton trucks under 8600lbs GVRW
5.7L 350 96 (L31) (Vortec) light duty, 2-bolt main.
12530282 350 CID New 5.7L
1999-2000 Chevrolet, GMC CK1 (L31) M30 (exc. NM8)
1996-98 Chevrolet, GMC CK1,2 (L31)(5.7R) M50, M30 (exc. NM8)
1996-2002 Chevrolet, GMC G1,2 (L31)(5.7R) M30
Engine-Specific Content: Crankshaft Hub, Front Cover, Oil Pan, and Valve Rocker Cover
Notes: For 2001 G-van application, service engine block contains English threads. May require Valve Covers to be transferred from original engine for some applications.

12530283 (4 bolt mains) $2069 from Summit On sale from Jegs for $1899

The reman version 12530283-R is $1729 from Jegs(no GM warranty though)

L31 Vortec 350 HD 3/4 ton and 1 ton trucks over 8600gvrw
5.7L 350 96 (L31) (Vortec) (HD), 3/8” stem exhaust valves and hardened inserts installed, 4-bolt main.
12530283 350 CID New 5.7L
1996-2000 Chevrolet, GMC CK2,3 (L31) MT1 (exc. NM8, KL5)
1996-2000 Chevrolet, GMC CK2,3 (L31)(5.7R) MW3 (exc. NM8)
1996-2002 Chevrolet, GMC G2,3 (L31)(5.7R) MT1
1996-99 Chevrolet, GMC P3 (L31)(5.7R) MW3, MT1 (exc. NM8, KL5)
Engine-Specific Content: Crankshaft Hub, Front Cover, Oil Pan, and Valve Rocker Covers
Notes: For 2001 G-van applications, service engine block contains English threads. When used for 2001 and 2002 vehicles, must also use 2000 MY Starter/Trans/Eng mounting bolts.

GM came out with a new crate engine last year, the 357hp-350. Its a 4 bolt Vortec 350 with the 357hp camshaft installed.
This is the complete SP350/357HP Vortec 350 for $4350
Chevrolet Performance SP350 Deluxe Crate Engines-longblock 19367082

SP350/357hp-Deluxe-with intake, carb, distributer, plugs and plug wires

Turnkey-19367084-$5550- includes all Deluxe kit in addition it has: front serpentine belt drive, water pump, a/c compressor

Basically a 4 bolt Vortec 350 with a roller cam.
357 HP @5500 RPM
407 LB-FT @4000 RPM

GM roller Camshaft GM part # 12677151 $315 from Summit

Camshaft Type (P/N 12677151): Hydraulic roller
Camshaft Lift (in): 0.473" intake / 0.473" exhaust
Camshaft Duration (@.050 in): 215° intake / 223° exhaust

(For comparison the stock 1996-2003 Vortec 305/350 roller cams have duration @ 0.050" lift of 191º/196º I/E and lift, using stock 1.5:1 rockers in 0.412"/0.428" with a 111ºLSA) On the GEN 1-E L30 305 it made 30hp@2800rpm/285lb/ft torque @ 2800rpm.
On the GEN1-E Vortec 350 rpo L31 it was rated at 255hp@4600rpm/330lb/ft torque@2800rpm.

Cam is around $300. Fast has one ordered. Basically a LT4 Hotcam that will drop into a Vortec engine.

I know of a guy running this roller cam in a Vortec 350 and he likes it. The SP350/357hp cam is designed to be a drop in replacement for the Vortec 305/350 and will work with the Vortec head retainer to valve seal clearance and the stock valve springs.


View user's profile Send private message
Display posts from previous:
Reply to topic Page 1 of 1
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum