Build & swap of a SBC in a GMT800 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Mykk · 10-19-2008, 11:05 AM

Hello everyone, here is my SBC build & swap.

I'll let the pics do most of the talking

bored .040" over, ring scuff on cylinder wall disappeared

zz4 forged crank & rods balanced with H345NCP-40 pistons & a new flexplate & dampener

LT4 Hot Cam
.525"/.525"
218/228
112+4

Mykk · 10-19-2008, 11:06 AM

.004" from deck, .039" compressed head gasket thickness, .043" quench height - 10.2-1 compression

Mykk · 10-19-2008, 11:06 AM

The swap: pulling the 4.3L & replacing with this Vortec 357ci

New 2800-3200rpm stall locking torque converter built for this swap (on the left, stock on the right) for the 4L60E .

Mykk · 10-19-2008, 11:08 AM

LSx to SBC adapter plates using GMT800 4.8l-5.3L motor mounts

Mykk · 10-19-2008, 11:09 AM

here's what I love about this swap.

Factory 4.3L V6 with bolt on's:

Built 357ci SBC with 4.3L v6 bolt on's

And here she is running, poorly. I'm still working out a few bugs and working on the computer tune.

YouTube - 2004 Silverado: Vortec 357ci SBC

Cheers ~Mykk

trailwart · 10-19-2008, 02:12 PM

are you running a gear drive?? are you having issues with the knock sensor?? what issues with the tune are you having??

Mykk · 10-19-2008, 02:21 PM

Yes a geardrive, the knock sensors sensitivity is turned way down in the tune. There is no false KR.

One bank thinks it's seeing an oxygen leak and adding a ton of fuel while the other bank is pulling some fuel. And that extremely out of whack air fuel ratio is causing a lack of power and missfires at higher rev. Problem is, I can't find any evidence of a leak. I replaced the lower intake manifold & gaskets, header gaskets & O2 sensors. There dont appear to be any vacuum leaks, there aren't any exhaust leaks yet that bank is still adding fuel.

ton*loc · 10-19-2008, 03:21 PM

try using the different im gasket i think it is felpro 1255 or 1250 something like that. my buddy had a problem just like you are having

Mykk · 10-19-2008, 03:32 PM

I used a Dorman manifold 615-300 and supplied gaskets. Wich are the updated "problem solver" gaskets.

But I'd be interested to hear more of your buddies problem.

djracer · 10-19-2008, 09:36 PM

Sweet looking setup. I built a vortec headed tbi injected stroker motor and it took a while to get the bugs out. Good luck on your issues.

Super73 · 10-19-2008, 10:14 PM

Very interested to see what it does.. I'm helping a buddy with a Patriot Vortec headed 327 with much bigger cam in a 64 backed with a M21.. Much different build though.

Pyrotechnic · 11-04-2008, 03:05 AM

Very cool swap. Also seen this done using S10 V8 adapter plates and the 4.3 mounts but your method using the LS adapter plates and V8 mounts looks nicer. Might surprise some of the LS powered trucks ?

combustion · 11-04-2008, 07:56 AM

Quote:

Originally Posted by Mykk

Yes a geardrive, the knock sensors sensitivity is turned way down in the tune. There is no false KR.

One bank thinks it's seeing an oxygen leak and adding a ton of fuel while the other bank is pulling some fuel. And that extremely out of whack air fuel ratio is causing a lack of power and missfires at higher rev. Problem is, I can't find any evidence of a leak. I replaced the lower intake manifold & gaskets, header gaskets & O2 sensors. There dont appear to be any vacuum leaks, there aren't any exhaust leaks yet that bank is still adding fuel.

im big time into the honda world, and this is also one problems that occurs when you cross out the oxygen sensors. when you cross the wires of the sensors, the computer sees the opposite banks and tries to adjust, but it never does because in fact ists reading the opposite bank

Super73 · 11-04-2008, 12:59 PM

Double check you don't have a fualty O2 sensor by puting them in each others places.

Pull your plugs and make sure they all look the same.

If you have a plug that is not firing, it's going to skew the one side to show extreamly rich in comparison to the "lean" bank when in all reality, both banks would be lean if that one plug was firing properly.

Sounds like you have a data logger, log misfires. What ever cyl has the highest count of them, start there.

10-19-2008, 11:05 AM	#1
Mykk Registered User Join Date: Apr 2005 Location: Prescott Az Posts: 55	Build & swap of a SBC in a GMT800 Hello everyone, here is my SBC build & swap. I'll let the pics do most of the talking bored .040" over, ring scuff on cylinder wall disappeared zz4 forged crank & rods balanced with H345NCP-40 pistons & a new flexplate & dampener LT4 Hot Cam .525"/.525" 218/228 112+4 Last edited by Mykk; 10-19-2008 at 11:11 AM.

10-19-2008, 11:06 AM	#2
Mykk Registered User Join Date: Apr 2005 Location: Prescott Az Posts: 55	Re: Build & swap of a SBC in a GMT800 .004" from deck, .039" compressed head gasket thickness, .043" quench height - 10.2-1 compression Last edited by Mykk; 10-19-2008 at 11:33 AM.

10-19-2008, 11:06 AM	#3
Mykk Registered User Join Date: Apr 2005 Location: Prescott Az Posts: 55	Re: Build & swap of a SBC in a GMT800 The swap: pulling the 4.3L & replacing with this Vortec 357ci New 2800-3200rpm stall locking torque converter built for this swap (on the left, stock on the right) for the 4L60E . Last edited by Mykk; 10-19-2008 at 12:30 PM.

10-19-2008, 11:08 AM	#4
Mykk Registered User Join Date: Apr 2005 Location: Prescott Az Posts: 55	Re: Build & swap of a SBC in a GMT800 LSx to SBC adapter plates using GMT800 4.8l-5.3L motor mounts

10-19-2008, 02:12 PM	#6
trailwart Registered User Join Date: Mar 2003 Location: michigan Posts: 356	Re: Build & swap of a SBC in a GMT800 are you running a gear drive?? are you having issues with the knock sensor?? what issues with the tune are you having?? __________________ 72 chevy 3\4 ton 4 speed 4x4 84 1\2 ton 4x4 (gone but not forgotten, thanks for the memories) 1999 suburban 4x4 1982 chevrolet S-10 V-8 (Thanks uncle EARL)

10-19-2008, 02:21 PM	#7
Mykk Registered User Join Date: Apr 2005 Location: Prescott Az Posts: 55	Re: Build & swap of a SBC in a GMT800 Yes a geardrive, the knock sensors sensitivity is turned way down in the tune. There is no false KR. One bank thinks it's seeing an oxygen leak and adding a ton of fuel while the other bank is pulling some fuel. And that extremely out of whack air fuel ratio is causing a lack of power and missfires at higher rev. Problem is, I can't find any evidence of a leak. I replaced the lower intake manifold & gaskets, header gaskets & O2 sensors. There dont appear to be any vacuum leaks, there aren't any exhaust leaks yet that bank is still adding fuel. Last edited by Mykk; 10-19-2008 at 02:34 PM.

10-19-2008, 03:21 PM	#8
ton*loc Registered User Join Date: Feb 2008 Location: sioux city iowa Posts: 178	Re: Build & swap of a SBC in a GMT800 try using the different im gasket i think it is felpro 1255 or 1250 something like that. my buddy had a problem just like you are having __________________ 1986 chevy c10 in the "build" process as we speak 358 flat tops, vortec heads, .500 lift cam, NOS power shot plate system, yada yada yada MMA PIX http://www.clgpix.com/MMA/Fighters/F...C/CoteTony.htm MMA RECORD 24-5

10-19-2008, 03:32 PM	#9
Mykk Registered User Join Date: Apr 2005 Location: Prescott Az Posts: 55	Re: Build & swap of a SBC in a GMT800 I used a Dorman manifold 615-300 and supplied gaskets. Wich are the updated "problem solver" gaskets. But I'd be interested to hear more of your buddies problem. Last edited by Mykk; 10-19-2008 at 03:42 PM.

10-19-2008, 09:36 PM	#10
djracer Registered User Join Date: Feb 2001 Location: Wetumpka, Al, U.S. Posts: 8,891	Re: Build & swap of a SBC in a GMT800 Sweet looking setup. I built a vortec headed tbi injected stroker motor and it took a while to get the bugs out. Good luck on your issues. __________________ Kevin Special Thanks to All who have helped on the TRUCK! My Pass Time Show http://s129.photobucket.com/albums/p...Chapter1-0.mp4 So Far my best Times are: Motor only: 6.44 1/8 @ 104.13 10.39 1/4 @ 125.83 Nitrous Times: 5.785 1/8 @ 118.65 with a 1.336 60ft 9.168 1/4 @ 142.58 with a 250 shot dead out of the hole!

10-19-2008, 10:14 PM	#11
Super73 Registered User Join Date: Nov 2007 Location: Bay Area, Ca Posts: 2,841	Re: Build & swap of a SBC in a GMT800 Very interested to see what it does.. I'm helping a buddy with a Patriot Vortec headed 327 with much bigger cam in a 64 backed with a M21.. Much different build though. __________________ ------Motor---------------Bottle 60'---1.53---------------1.41 1/8---6.58 @ 105.92----5.87 @ 118.41 1/4---10.38 @ 126.97----9.24 @ 142.49

11-04-2008, 03:05 AM	#12
Pyrotechnic Registered User Join Date: Feb 2007 Location: Austin, TX Posts: 3,930	Re: Build & swap of a SBC in a GMT800 Very cool swap. Also seen this done using S10 V8 adapter plates and the 4.3 mounts but your method using the LS adapter plates and V8 mounts looks nicer. Might surprise some of the LS powered trucks ? __________________ 1977 GMC Sierra Grande

11-04-2008, 12:59 PM	#14
Super73 Registered User Join Date: Nov 2007 Location: Bay Area, Ca Posts: 2,841	Re: Build & swap of a SBC in a GMT800 Double check you don't have a fualty O2 sensor by puting them in each others places. Pull your plugs and make sure they all look the same. If you have a plug that is not firing, it's going to skew the one side to show extreamly rich in comparison to the "lean" bank when in all reality, both banks would be lean if that one plug was firing properly. Sounds like you have a data logger, log misfires. What ever cyl has the highest count of them, start there. __________________ ------Motor---------------Bottle 60'---1.53---------------1.41 1/8---6.58 @ 105.92----5.87 @ 118.41 1/4---10.38 @ 126.97----9.24 @ 142.49 Last edited by Super73; 11-04-2008 at 01:00 PM.



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