L31 vortec upgrade

[Rouge Nova]

I have a 2000 Chevy Tahoe limited with a 5.7 vortec under the hood. I’m trying to do some mods on it to get it to 350 or 400 HP but I don’t know where to start. Any advice on what are some good mods to start with?

 

[Schurkey]

Upgrade to GM HT383E crate engine intended for L31 replacement in 1500 applications.

www.chevrolet.com/performance-parts/crate-engines/small-block-engine/ht-383e

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You'd end up a bit shy on horsepower, but with better low-rpm torque.

 

[Erik the Awful]

Before you start down this path, make sure you've done a tune-up and everything's running properly. Make sure your brakes are in good shape and working to their full potential.

Any advice on what are some good mods to start with?

As you say you're wanting to work your way to that goal, I'd start with improving the exhaust. DIY is the best quality for dollar, but you have to have the tools and skills. If you go duals you'll want an X or H pipe. Two-into-one is very popular and doesn't give up much, if anything, to a dual exhaust if you make sure that merge pipe is at least 3". You'll probably also want headers to get to your desired horsepower. Long tubes fit well and work well on these trucks.

Don't bother with "cold air" intakes. The factory intake draws cool air from the fender. The best improvement there is to open up the sheetmetal for the air to get into the intake tract. Somebody who owns a Vortec truck might be able to make a recommendation.

Getting to 350-400 horsepower is going to require a cam change at some point. Your factory injection system should be able to handle it with a re-tune.

 

[L31MaxExpress]

Before you start down this path, make sure you've done a tune-up and everything's running properly. Make sure your brakes are in good shape and working to their full potential.


As you say you're wanting to work your way to that goal, I'd start with improving the exhaust. DIY is the best quality for dollar, but you have to have the tools and skills. If you go duals you'll want an X or H pipe. Two-into-one is very popular and doesn't give up much, if anything, to a dual exhaust if you make sure that merge pipe is at least 3". You'll probably also want headers to get to your desired horsepower. Long tubes fit well and work well on these trucks.

Don't bother with "cold air" intakes. The factory intake draws cool air from the fender. The best improvement there is to open up the sheetmetal for the air to get into the intake tract. Somebody who owns a Vortec truck might be able to make a recommendation.

Getting to 350-400 horsepower is going to require a cam change at some point. Your factory injection system should be able to handle it with a re-tune.

2nd exhaust and headers, especially on the 1500 trucks that used the dinky little 1-7/8" pipes. Luckily my L31 van had easy room to grow since it was dual 3" to the muffler from GM. It ran well with a dual 3" in, single 4" out muffler and then I added shorty headers and high flow metallic core thunderbolt cats. Later I added tri-ys and it picked up a good bit more torque.

A volant intake is sealed and flows a lot better than the stock restrictive garbage.

 

[Idaho_z71]

I have a 2000 Chevy Tahoe limited with a 5.7 vortec under the hood. I’m trying to do some mods on it to get it to 350 or 400 HP but I don’t know where to start. Any advice on what are some good mods to start with?

@shurkey Is right about the HT383E. I put one in my 98 GMC and made a world of difference. If you want even more power you could do a mild cam.

 

[PlayingWithTBI]

@shurkey Is right about the HT383E. I put one in my 98 GMC and made a world of difference. If you want even more power you could do a mild cam.

OR... go with a Blue Print long block

www.blueprintengines.com/products/383-ci-stroker-crate-engine-small-block-gm-longblock-bp38318ct1

GM SB Compatible 383 c.i. Engine - 436 HP - Long Block

BluePrint Engines 383 c.i. small block GM style stroker crate engine - longblock. Includes 30 month / 50,000 warranty & BPE Dyno Promise. Part #: BP38318CT1

blueprintengines.com

 

[Schurkey]

OR... go with a Blue Print long block

www.blueprintengines.com/products/383-ci-stroker-crate-engine-small-block-gm-longblock-bp38318ct1

GM SB Compatible 383 c.i. Engine - 436 HP - Long Block

BluePrint Engines 383 c.i. small block GM style stroker crate engine - longblock. Includes 30 month / 50,000 warranty & BPE Dyno Promise. Part #: BP38318CT1

blueprintengines.com

OP lives in California. Blueprint long block says "not for use with EGR", and there's no CARB approval.

Reasonably sure the GM HT383E is 50-state emissions-legal until you screw with it. Therefore, no cam change, no re-tune, no this-or-that. Drop it in according to GM instructions, done. OTOH, I can't find anywhere on the GM web site that says the HT383E is emissons-legal. (I thought that was the whole point of the final "E".) The installation guidelines specifically state that it's for "off-highway use" only. So the OP may be well-and-truly screwed by Commiefornia.

 

[GoToGuy]

If you live in state with emissions laws, inspections, you are limited at what you can do. Not everyone can just rip everything out they don't like.
The next engine replacement will be the HT383E, new after cat duals, and the upgraded fuel injection. No hassle with CA smog Nazis, performance and reliability, has warranty also.
Good luck!

 

[98 Nitro]

As long as it looks stock and passes the sniffer no one will know it is a 383.

 

[PlayingWithTBI]

I can't find anywhere on the GM web site that says the HT383E is emissons-legal. (I thought that was the whole point of the final "E".) The installation guidelines specifically state that it's for "off-highway use" only. So the OP may be well-and-truly screwed by Commiefornia.

Yeah, it doesn't look like it is either.

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I guess OP can go with a GMPP or Blue Print 350?