5.7 vortec performance?
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5.7 vortec performance? Hey guy's I need some help on finding performance parts for my old 5.7 vortec. I'm wanting to build it more for towing, since I off road a lot. Any help would be greatly appreciated.
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I have been looking around for some But it's hard to find something that wont mess with the pcm. They told me at comp cams when I called that they could cut something out for me but I don't know what I really need in a cam. I would like to have more vacuum for the power brakes and more torque for pulling.
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Gear swap. Without any supporting mods a cam swap on a Vortec will mostly just move the existing torque higher in the RPM range, not really make much more. Fiddling around with the cam to make more low end than there is now while also trying to make more vacuum will probably result in a disappointment for the money spent. Increasing lift without increasing duration will give you more torque without affecting power band much, but your heads are limited without doing some machine work or swapping springs. Gears don't require any PCM change other than speedo calibration which you can do with an old Hypertech that's probably on ebay for $50. If you've gone to taller tires that would be the same as going with less gear already so more gear would help out anyway.
Check your glove box for codes to see what gear you have in it now. The bad news would be if you have a 3.08 because you'd also need to move to a new carrier(s) to move up, but junkyards and ebay are always out there vs new. Here's a few codes:
GQ1 -- AXLE REAR, STD RATIO
GT4 -- AXLE REAR, 3.73 RATIO
GT5 -- AXLE REAR, 4.10 RATIO
GU4 -- AXLE REAR, 3.08 RATIO
GU5 -- AXLE REAR, 3.23 RATIO
GU6 -- AXLE REAR, 3.42 RATIO
G80 -- AXLE REAR, LIMITED SLIP (POSITRACTION)
HC4 -- AXLE REAR, 4.56 RATIO
Check your glove box for codes to see what gear you have in it now. The bad news would be if you have a 3.08 because you'd also need to move to a new carrier(s) to move up, but junkyards and ebay are always out there vs new. Here's a few codes:
GQ1 -- AXLE REAR, STD RATIO
GT4 -- AXLE REAR, 3.73 RATIO
GT5 -- AXLE REAR, 4.10 RATIO
GU4 -- AXLE REAR, 3.08 RATIO
GU5 -- AXLE REAR, 3.23 RATIO
GU6 -- AXLE REAR, 3.42 RATIO
G80 -- AXLE REAR, LIMITED SLIP (POSITRACTION)
HC4 -- AXLE REAR, 4.56 RATIO
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Agreed that the right gears will make the biggest difference. Other than that, some full length headers and good exhaust will help. A not too expensive mod would be to buy a typical 4bbl edelbrock performer type intake for vortec heads and then use a 4bbl to TBI plate to adapt your TB. That and some heads, edelbrock sells two versions that would be great, would give you a decent kick.
http://www.ebay.com/sch/items/tbi+ad...=445962_446022
http://www.ebay.com/sch/items/tbi+ad...=445962_446022
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Thanks for the replies guy's. I already have 3.73 gears with limited slip front and rear. I have been thinking of some shorty headers, would that help any or go with full length headers?
On some other stuff I haven't really given much detail about the truck; 1998 k1500 5.7 vortec 2 chamber flowmaster's true duals with a nv4500 tranny swap(94 model tranny) and a pcm reflash for the 5spd from pcm's for less. I think I also had them tune it up, but can't really remember. Also as mentioned above I upgraded the ignition system and spider injection.
Just wondering if the 0411 swap would help?
On some other stuff I haven't really given much detail about the truck; 1998 k1500 5.7 vortec 2 chamber flowmaster's true duals with a nv4500 tranny swap(94 model tranny) and a pcm reflash for the 5spd from pcm's for less. I think I also had them tune it up, but can't really remember. Also as mentioned above I upgraded the ignition system and spider injection.
Just wondering if the 0411 swap would help?
Last edited by johnboy98; Nov 2, 2013 at 09:50 PM.
Withousnding some coin, the 0411 swap is by far the ebst/cheapest mod. I gained 2-3 mpg empty, and torque over the entire rev range. For <$200, it can't be beat. Since you have a manual, the 3.73 is a great gear paired with the NV4500. Thats exactly where I'm looking to go long-term. You've got the gearing to do it. I'd say do an 0411, and a cam swap,a nd evaluate it then. If you want to spend more money after that, you can do a multi-port conversion, but it's not cheap. However, it's probably cheaper than most people can do a 6.0 or a 454/8.1l swap for. I JUST started a thread actually, as I'm doing a COP/Sequential injection conversion to my Vortec 350.
mine busted a timing chain a while a go, in the process of pulling it apart I realized the stock 190k mile spider injection was no good (not to mention a performance nightmare), I took a couple weeks and swapped some stuff to it, worked really well and it gained a TON of midrange torque and noticeable hp up top too, I put a 95 lt1 f body cam in it so it took it from the stock 191/196 .398/.410 cam to the 202/207 .455/.465 (w 1.55 rockers). Not a huge cam but it is 10* of duration, I put a cheap set of roller tip comp magnum rockers on it to try and save the old valve guides, ls7 lifters, comp pushrods, swapped on ls6 valve springs the comp retainers and locks and a new set of fel pro Viton valve seals........I had a tpi intake laying around the shop so I got the vortec base from edelbrock and adapted it on with a set of svo 30lb injectors I had on the shelf and an old BBK 52mm TB I had laying around.....I did a mild port job on the plenum and base.....took a bunch of wiring extending and I had to make a harness for the injectors, also had to make a bracket to move my AC up and over a couple inches to clear the throttle body.........heres a pic of it it runs awesome and it didn't cost much to do it all.
Last edited by quik95lt1; Jan 3, 2014 at 03:29 PM.
not at all its designed to bolt right together and fit on the vortec heads.........the injectors I just had to re plumb the fuel lines and you just lop the stock harness end off and make a harness to go to the 8 separate lm1 injectors....
Ohh, ok. Thought you meant you had to mod the injector holes themselves
