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Discussion Starter · #1 ·
Hey guys,
new to the forum here. What i have is a 2000 vortec 350 out of a isuzu npr box truck. the heads are not the 906 vortec heads they are the other number vortec heads. i am looking to get over 400 hp but i wanna stay within 1500. any way you guys can give me list of parts thay would make a good combanation. for street/strip. thanks in advanced. i will be sending the motor out to get done but i would like a parts list for what i need to order to ressambly and have done to the heads
 

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so you want more than 400hp, but less than 1500hp. That's a biiiiiiiiiiig margin.:drunk:

Do you want it naturally aspirated? turbocharged? supercharged? twin turbos?

What does your budget allow? CNC heads, iron aftermarket heads, or are you going to make use with the stock cylinder heads (port them or leave them alone?)

What do you want? Do you want it fast and cheap, fast and reliable, or what?

What vehicle is this engine going into (it's from a Isuzu cabover truck)? What transmission (and torque converter if applicable) and rear gears are in said car?
 

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Discussion Starter · #4 ·
i am flexable on cost since this dont need done right away. the vehicle it is going into is a 96 s10 stepside pickup with 383 posi gears. the izusu is what the motor came from. i would like around are over 400. stay with pump gas have something reliable but yet able to hammer it out when need. this trucks not going ot be raced. mayb to the strip once r twice to play around. also useing the stock trans right now which iss a 4l60e untill i can upgrade
 

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basic stock rebuild shortblock add balance engine components,careful blue print and high quality machine work to deck/square/align hone block, buy/build a good set of vortec heads with modifications for bigger cam,including mild porting especially on exhaust side,,,cam and kit to fit performance desires,intake and fuel management tuned to below parts,good quality headers and full free flow exhaust
 

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To get you started

Hey guys,
new to the forum here. What i have is a 2000 vortec 350 out of a isuzu npr box truck. the heads are not the 906 vortec heads they are the other number vortec heads. i am looking to get over 400 hp but i wanna stay within 1500. any way you guys can give me list of parts thay would make a good combanation. for street/strip. thanks in advanced. i will be sending the motor out to get done but i would like a parts list for what i need to order to ressambly and have done to the heads
First have the block and heads inspected to be sure they're not cracked and are suitable to build with. If they are:

• Bore the cylinders to the smallest oversize that cleans them up
• Inspect the crank, turn if necessary. Polish if OK
• Inspect the rods, remove/replace rod bolts w/ARP then resize them

There are cheap rebuild kits from places like Northern and Rock Auto. Based on your needs and budget you can decide where to go.

Don't go too big on the cam if this is a street engine! Over-camming it will make you miserable. To name a few things you need to pay attention to: the cam has to match the way you drive, the weight, gear ratio, and compression ratio, and the compression ratio has to be compatible w/the fuel used. Build it w/matching engine components that will work as a unit and you'll be happy w/the results. There are many threads on this here and elsewhere.

Be aware that there are two compression height pistons that you'll see. One is 1.54" (shorter by 0.020") and is called a rebuilder piston. The other is the stock compression height of 1.56". Regardless of which you end up with, pay attention to the quench measurement.

Rebuild guides/books

Heads:
Vortec heads
Milling decks

Valve Train:
Valve spring installed height
Points to check
Geometry
Adjust lifters
Cam break in

Other:
First start up
HEI distributor/Timing info
Engine section

Good luck.
 

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Discussion Starter · #9 ·
hey guys thanks for your responses if there any body that has any parts specificlly in mind please feel free to let me know part numbers would be great thanks for the help here
 

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For reliability I wouldn't scrimp on quality machine work. The directions outlined on a good quality rebuild with quality American parts and ported vortec heads should net you a bit over 400. Depending on exhaust and intake and such I can't guarantee anything though. For a street driven S10 though, it'll be plenty of power to put that posi to work.:D

Here's a budget vortec head shootout article. Good read.
Eight Budget Small Block Chevy Heads Tested - Car Craft Magazine

One last thing... when building a street engine, build for torque. Most of the time you'll be cruising, and you want the engine to be responsive and hit hard "right here right now", rather than something that thrives up high (machine work is even more critical at higher rpms. The forces the connecting rods see go up exponentially (kinda like interest on a mortgage) with RPM.


If you find a way to do this, contact me immediately. I want to do the marketing for the product.
Junkyard 350 (or two to get one that runs), and a heavy shot of nitrous. Of course, you'd be driving a time bomb.
 

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Better check yourself, son.
I see some humor in it (400hp for dirt cheap... better get good at swapping engines), but budget builds are possible. Let's try to help the guy out. Maybe he's new.

Granted, for a "done right" reliable 400+hp, I think the budget of $1500 wouldn't be enough. I highlighted my thoughts on a street oriented vortec sbc build in my other posts here.

Heck, maybe even have the oem cast internals checked out, deburred, and balanced, it might hold together. I wouldn't do it, but if it's more of a street cruiser/bruiser where it'll be cranking out that 400hp just once in a while, I don't see why he'd need aftermarket rods. The vortec engines (and I think any sbc built since 1986) has roller lifters, which while not the best, aren't bad for a low buck build. The vortec heads are pretty good in stock form, so I think we have a great start.

For inexpensive parts, find a used dual plane intake manifold, and the stock GM HEI is a good unit, and while I'm sure you'd be able to see some gains going to an aftermarket performance ignition, I'm thinking about budget parts here.
 

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Discussion Starter · #15 ·
as i said i do have 2 vortecs here, both run, i am new to the enigine building process. the trucks not going to be beat on on a everyday basis just driven for fun and on the gas once in a while. im looking at staying around 1500 but i can move up in price as i dont need this motor built right away,
 

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Back in July I purchased a BM 144 blower for 800. They comonly sell around a 1000. Cannot reason why 400+ hp for 1500 is out of the question. Budget yourself and get a plan together, it will be done.
 

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Discussion Starter · #18 ·
i am trying to do as much research as possiable to make a good reliable and strong motor hopefully the good feedback keeps comeing ive been reading about ls6 valves and springs/. anyone know anything about that
 

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The beehive Ls6/ Series 2 v6 spring and retainer is a slight upgrade from the stock springs. Drop on to the valves. The series 2 and vortec heads have the same valve stem diameter. Ther are pictures of the mounted ls6 springs on 906 vortecs in my photo journal.
 

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i am trying to do as much research as possiable to make a good reliable and strong motor hopefully the good feedback keeps comeing ive been reading about ls6 valves and springs/. anyone know anything about that
1. L31 castings are thin-wall and crack-prone. You may have to magnaflux several sets of them to find two valid players.
2. Yes, you can gain more lift with different springs, but that doesn't address the O.D. of the valve guide. Without cutting the guides, you're still limited to single springs with no damper and stock seals. Try running a roller cam with small diameter single springs. Good luck. Best way is to shorten the guide and reduce the diameter of the guide. Then you can use the correct springs with the correct diameter and dampers for a hydraulic roller cam.
3. Rocker studs are pressed-in and will not tolerate more than about 260 lbs over the nose until they begin pulling out of the heads. You can fix this by drilling and pinning the stock studs or pulling them out, milling the stud pedestal area and tapping for screw-in studs. If you don't mill the heads at the stud area, the screw-in studs will sit too high and you won't have enough thread to adjust the valves.
4. The holes where the pushrods come up through the heads will have to be clearanced.
By the time you get all this done, you will have more invested in these heads than they are worth and they still won't perform as well as a dedicated aftermarket head.

Look at these #12410-02 assembled cast iron heads from Racing Head Service......
Pro Torker Assembled Cylinder Head Racing Head Service (RHS) 12410-02 - Pace Performance Parts
A complete set of heads with hydraulic roller springs, screw-in studs and guide plates, $958 for the set and they'll flow better than the L31 Vortecs and they won't crack as easily. They'll easily make 400 hp and 450 ft/lbs of torque with a well-matched set of components.
I can guarantee you'll have more than that invested in a set of L31 heads by the time you upgrade them to the level of these RHS heads.
 
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