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Username Post: 400Hp can it be done?        (Topic#357755)
N8sToolz 
Very Senior Member
Posts: 2324
N8sToolz
Age: 33
Loc: N 42° 53.290' W71° 34.1...
Reg: 10-23-03
08-21-19 05:52 PM - Post#2773784    

Hey all, it's has been awhile since I've been around but I know you can help out.

I have a project in the pipeline that I have some ideas with. 98 K2500 Pickup 5.7 it was an old mans truck in great shape. The motor has locked up and I bought it at a great price. The plan is to do a cab off rehab to the truck. Sandblast and paint frame, new lines, overhaul trans with upgrades.. Basically make a nice turn key truck that I can do a few long haul trips with towing and daily it (Plow my drive too).

I already picked up a used motor that I could probably just drop in but of course I need to upgrade here. I want to try and build an LS fighter that will keep up with a modern truck when at work.

Is it possible to get to 400hp (or at least how close) using the stock EFI? What do you think I will need to get there? I am already planning on stripping it and sending it to the machine shop for checking over anyways. I'll probably do flat tops and cam with tune anyways, is there a better flowing head thats worth looking into?

Am I crazy? Or just



 


grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17389
grumpyvette
Age: 71
Loc: FLORIDA USA
Reg: 03-16-01
08-21-19 06:53 PM - Post#2773785    
    In response to N8sToolz

it would help a great deal if you let us know what LS engine year, displacement and the heads and block casting numbers and of course an idea as to the budget

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...



IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


Edited by grumpyvette on 08-21-19 07:02 PM. Reason for edit: No reason given.

 
N8sToolz 
Very Senior Member
Posts: 2324
N8sToolz
Age: 33
Loc: N 42° 53.290' W71° 34.1...
Reg: 10-23-03
08-21-19 07:22 PM - Post#2773789    
    In response to grumpyvette

Sorry about that, My plan is to use the 5.7 to build something comparable to a more modern 6.0 in a comparable truck power wise. Not to install a more modern engine in an older truck.



Edited by N8sToolz on 08-21-19 07:23 PM. Reason for edit: No reason given.

 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17389
grumpyvette
Age: 71
Loc: FLORIDA USA
Reg: 03-16-01
08-22-19 07:13 AM - Post#2773804    
    In response to N8sToolz

I can certainly provide a very well-proven list of SBC parts,
that can get you too that 400 hp level rather easily,
but the issue is similar in that you need to realistically plan the engine build and think about your budget, your skill level and the tools and a place you have access to,do the job.
the all too common problem most guys have is that they don,t take the effort and time to carefully plan
all too many guys just want to look at what they have and throw the parts they get at lower bargain price's together, and if you fail to take into account the component design characteristics thats a recipe for less than ideal results.

lets start with the basics
Do you think, you can you use the existing SBC 350 block after you've removed the rotating component assembly and have inspected the block?
yeah, it might require a rebore and cylinder hone, you can of course , build a 350 if you can,re-use most existing parts ,to do so,
BUT I would be seriously considering building a 383 SBC, as its one of the most cost-effective routes to decent power per dollar spent.
the KEY is building the engine for maximum durability, and selecting the best cylinder heads you can afford, and of course,
matching the components, selected, to match the drive train gearing, and intended power band, and rpm range and fuel octane available..

threads you should read, all the info may not directly match your intended build but youll want the vast majority of the knowledge

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

https://www.hotrod.com/articles/ccrp-1209-ei ght-bu...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...

http://garage.grumpysperformance.com/index.php?thr...


IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


Edited by grumpyvette on 08-22-19 07:21 AM. Reason for edit: No reason given.

 
japete92 
"5th Year" Silver Supporting Member
Posts: 1249
japete92
Loc: No. Virginia
Reg: 01-18-13
08-22-19 10:19 AM - Post#2773815    
    In response to grumpyvette

Get to 400 hp on a 350? Sure, not hard as Grumpyvette has stated. But, in my opinion, the sbc '383' would be better 'bang for the buck'.

To amplify to what Grumpyvette said (a thorough reading of his sticky on building a 383 is recommended):

The '383' is a great choice. My opinion, focus on low end torque unless you are seriously racing. A goal of +400 lb ft between about 2500 to 4000 rpm is where I would place emphasis. Keep red line in low to mid 5k rpm and let hp basically 'fall out' (a max around 375-400?).

A '383' engine like that does not require headers, exotic cam/lifters/springs, nor super flowing expensive heads. Mostly just QUALITY 'plain Jane' parts get there.

Want more, spend more and give up some reliability and normal drivability.

Pete





 
Rick_L 
Honored Member
Posts: 27651
Rick_L
Loc: Katy, Tx, USA
Reg: 07-06-00
08-23-19 03:42 PM - Post#2773903    
    In response to N8sToolz

No one answered your other question, which was will the stock injectors support 400 hp.

I don't think there's any way. The injectors themselves are probably too small, and the ecu would have to be reprogrammed to suit your combination and fuel needs. You'd be better off with a carb or with an aftermarket EFI. And if you need to pass an emissions check, you probably couldn't.



 
grumpyvette 
Senior Chevytalk Moderator -- Performance Subject Matter Expert --
Posts: 17389
grumpyvette
Age: 71
Loc: FLORIDA USA
Reg: 03-16-01
08-23-19 06:53 PM - Post#2773918    
    In response to Rick_L

http://garage.grumpysperformance.com/index.php?thr...

IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!


 
1983G20Van 
Super Senior Member
Posts: 3776

Loc: Bedford, Texas, USA
Reg: 11-13-02
08-23-19 11:28 PM - Post#2773931    
    In response to Rick_L

  • Rick_L Said:
No one answered your other question, which was will the stock injectors support 400 hp.

I don't think there's any way. The injectors themselves are probably too small, and the ecu would have to be reprogrammed to suit your combination and fuel needs. You'd be better off with a carb or with an aftermarket EFI. And if you need to pass an emissions check, you probably couldn't.



The limit of the stock injectors is about 425 hp but the intake base needs to be ported and the TB opening opened up to use a larger TB to get the airflow needed. There is a company making much larger injectors for the spider as well but they are not cheap. IIRC they go as large as 72 lb/hr. The stock ones deliver about 24 lb/hr @ 70 psi. I have made more than 400 hp out of several of the Vortec trucks. The Black box PCMs can be a challange to tune. I suggest an 0411 or newer 03-05 Blue/Green PCM swap. The Mexico 5.7 GMT800s used the Blue/Green PCMs. My 97 Express van is getting a 383 that will make close to 500 hp. I am going to use a L31 marine dual plane mpi intake with an low profile edelbrock intake plenum and a 87mm LS2 Trailblazer SS throttle body. I have the EFI connection 24x reluctor and delco D585 LS truck coils. 0411 out of a 2002 8.1 van with the matching drive by wire pedal and TAC module. Will be using a flex fuel 5.3 Tahoe operating system in the 0411 so that I can run E85. The 383 is 11:1 with ported heads that have 210cc intake tunners. The cam is small for a 383 but still going to run Rhoads VMax lifters. I am going with the bigger runner/higher flow/ shorter cam duration/higher ratio rocker approach.

1983 G20 Van, 350 TPI, Ported 906 Vortecs, Edelbrock 3817 Base, ASM oversize runners. Reed Custom Roller cam, 700r4, 12 bolt with 3.08 gears, Doug Thorley Tri-Y headers, true duals


Edited by 1983G20Van on 08-23-19 11:34 PM. Reason for edit: No reason given.

 
1983G20Van 
Super Senior Member
Posts: 3776

Loc: Bedford, Texas, USA
Reg: 11-13-02
08-25-19 11:59 AM - Post#2774008    
    In response to 1983G20Van

I will also say for the goal you have for the truck it does not need 400 hp as much as it could use 400 ft/lbs or more of torque. I had my Express van put down 272 rwhp and 330 rwqt through a 4L85E in 2nd gear and a 9.5" 14-bolt using a stock GM cam and ported stock L31 intake with the stock spider. I had a set of 906 heads that had 0.020" shaved off them, LS6 valve springs on Comp 787 retainers and 2.02/1.60 valves. I used screw in studs and guide plates with hardened pushrods and non self aligning 1.7 roller rockers. Used a 0.016" compressed rubber embosed steel shim head gasket. Used a GM 395' marine cam. Doug Thorley tri-y headers into the stock dual 3" exhaust tubing. I used a walker dynomax bus muffler with dual 3" inlets and a 4" outlet into a duramax 4" tail pipe. It ran very well. The 3-ton van had alot of get up and go for having a 3.73 gear and 30.5" tall tires. Highway fuel mileage stayed very close to the stock 17-18 mpg. Since power peaked at 4,800 rpm I did not have to turn the motor much. WOT upshifts were programmed for 5,200 rpm.

https://youtu.be/bpPSgILR6wc

That exhaust setup has zero drone or resonance. The setup would also pull the 3 ton van up 6%+ grades at 70 mph without kicking down to 3rd or downshifting. Turned about 2,150 rpm @ 70.

https://youtu.be/UgwvwHzk74c

You don't need a 383 go get 400-425 ft/lbs of torque out of a Vortec head 350.





1983 G20 Van, 350 TPI, Ported 906 Vortecs, Edelbrock 3817 Base, ASM oversize runners. Reed Custom Roller cam, 700r4, 12 bolt with 3.08 gears, Doug Thorley Tri-Y headers, true duals


Edited by 1983G20Van on 08-25-19 12:14 PM. Reason for edit: No reason given.

 
scrambldcj8 
Silver Supporting Member
Posts: 2492
scrambldcj8
Loc: Belchertown, MA
Reg: 04-06-03
08-26-19 03:40 AM - Post#2774048    
    In response to 1983G20Van

  • 1983G20Van Said:

Used a GM 395' marine cam.

You don't need a 383 go get 400-425 ft/lbs of torque out of a Vortec head 350.






For those that might not know, that 395' cam is the RamJet 350/HT383 roller.

While a 383 is not needed. It's easier to get 400+Tq in a usable range for a heavy vehicle when starting with a 383.. ..the plus is the motor needs to be rebuilt anyway and the cost upgrade is fairly minimal. Why leave so much potential on the table when tuning will be required anyway?

Can you tell I am a fan of the 383/406 SBC...



 


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