INTERNAL ENGINE MODIFICATIONS Valvetrain |Heads | Strokers | Design | Assembly

Building a SBC

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Old Aug 20, 2008 | 10:08 PM
  #41  
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I chucked up the harmonic balancer in my brake lathe and removed enough material off the hub to compensate for the shims behind the reluctor wheel on the crank.

The March underdrive pulleys arrived. And than I moved the engine from the machine shop to the sales floor waiting to get loaded in the back of my truck







And there she will sit until Sept 12th, where I have the weekend of the 13th reserved for the install. I've a small team of gearheads willing to help for the cost of beer, so either by hook or by crook this project will get done.

Cheers ~Mykk
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Old Aug 20, 2008 | 10:16 PM
  #42  
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Looks good Mykk
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Old Aug 21, 2008 | 07:03 AM
  #43  
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nice "spare parts" room
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Old Aug 21, 2008 | 06:26 PM
  #44  
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I want to make up for the crappy cell phone pics from the past few days...

Pinned rocker studs



The pushrods get close to the side of the drilled out holes, but do not touch.



The march pulleys look good, even though this is a fuel injection block someone did drill it for a mechanical fuel pump, the block off plate is needed.



Opened up throttlebody port on the plenum. It's really thin right there at the gasket but doesn't cause any issues and matched the CFM-Tech throttlebody perfect.



The balancer after machining down the hub surface to maintain alignment because of using the valve spring shims to space the CKPS reluctor wheel



I don't think I mentioned this before, who ever pulled this intake from the original engine snapped off the heater hose fitting and split the boss in half. After cutting & grinding the old boss away than drilling & tapping a new hole for the pipe plug fitting...



And finally, the O2 bungs on the headers



Cheers ~Mykk
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Old Aug 21, 2008 | 06:37 PM
  #45  
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how much power do you expect?
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Old Aug 21, 2008 | 10:22 PM
  #46  
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Originally Posted by GMCtrk
how much power do you expect?
A sbc with vortec heads, 10-1 compression & LT4 hot cam is a proven 400+ HP motor... my downfall will be the L31 fuel injection. It has been rumored that the L31 vortec FI can support 400RWHP...

So, really, I don't know... all roads point to the 400 mark

Last edited by 04SilveradoMykk; Aug 21, 2008 at 11:57 PM.
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Old Aug 21, 2008 | 10:32 PM
  #47  
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A cam only SBC makes 400+!!??? That's more than a cam only 6.0
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Old Aug 21, 2008 | 11:44 PM
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Originally Posted by 04SilveradoMykk
A sbc with vortec heads, 10-1 compression &LT4 hot cam is a proven 400+ HP motor... my downfall will be the L31 fuel injection. It has been rumored that the L31 vortec FI can support 400RWHP...

So, really, I don't know... all roads point to the 400 mark
The stock L31 fuel injection can support only around 400 crank hp (or 330 rwhp), at least thats what I've read. The stock injectors/poppets are 19 lbers @ 3 bar.

A guy on another forum with a 383, stock vortec intake manifold, LT4 hotcam kit, ported vortec heads, headers, exhaust and a tune made 330 rwhp, 381 rwtq. I don't know what compression he has but I don't think you are going to be above 300 rwhp. Stock the L31 only dyno's at 210 rwhp.

On my stock long block L31 (stock cam, heads, etc) with 9 lbs of boost and everything else in my sig except intercooler, I dynoed 330 rwhp 449 rwtq.
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Old Aug 21, 2008 | 11:49 PM
  #49  
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Originally Posted by GMCtrk
A cam only SBC makes 400+!!??? That's more than a cam only 6.0
Taken from Carcraft Magazine that built a Vortec headed 350 with a LT4 Hot Cam & 1.6 rockers

http://www.carcraft.com/techarticles...ine/index.html

"...the combination of the roller cam and its additional rocker ratio revealed that these changes added significant power, making 401 hp at 5,600 rpm. This test illustrates that Vortec heads are certainly capable of a streetable 400 hp as well as excellent low-speed and midrange with 428 lb-ft at 4,200. With 15.5 inches of manifold vacuum at a 950 rpm idle, this is a very streetable package."

But again, like I said... the downfall will be the F.I. No matter how you look at it, the V8 will drive, perform and sound way better than the current 4.3L V6. And a reliable, daily driven 300 RWHP RCSB pickup is just fine by me.

Last edited by 04SilveradoMykk; Aug 22, 2008 at 12:04 AM.
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Old Aug 22, 2008 | 12:12 AM
  #50  
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I like the low end torque of the SBC.
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