2004 Silverado: 4.3L to SBC swap

Following the build of the SBC iintroduced in my very first Introductory post here on Hotrodders.

http://www.hotrodders.com/forum/hel...-az-142145.html


The 4.3L to V8 swap has begun:

Sept 6th, 08:

Parked the truck, removed a few body panels. Disconnected the battery, drained the coolant. Removed the radiator hoses, removed the accessory brackets- Alt & PS pump. Unplugged all of the engine sensor harnesses, unhooked the Y-pipe from the headers. Removed all of the bell housing bolts, disconnected the torque converter from the flexplate.





Modified the A/C bracket & spaced the A/C compressor to work with the tall valve covers.













Unhooked all of the engine wiring harness & brackets from the motor and began to pull.



This was the time to unbolt the rear ground straps & remove the Knock Sensor







And this is where I am at, after a short break and cool down from the 90+ degree heat out there.

This afternoon/evening I plan to change the torque converter out for my 3000 stall unit, change the motor mount brackets for the V8 ones, and splice the V8 fuel injector plug in onto the 4.3L harness.

Cheers ~Mykk


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Finished up day one by:

tossing the V6 motor mount brackets and bolted in the new V8's



Filled up the new 3000 stall locking torque converter and stabed it into place.



Started grafting the V8 plug to the harness



Repinned the PCM to match the V8, inclduding running two new leads





Tomorrow is another day

Cheers ~Mykk

Actually yea.

Day 2. Sept 07,08:

It's not 100% bolted in... lets call it 80%











I didn't have any intention to get the motor in today, but my buddy and I watched this little cloud directly above us balloon into a massive thunderstorm and we got the engine sitting in the engine bay just as it started to down pour.

The engine isn't completely on it's mount brackets. I have a feeling the trans slid forward in it's elongated slot on the cross member, enough to misalign the motor mounts up front. And the engine will sit 1.5" lower once it's completely on the mount brackets.

I've got a couple more bell housing bolts to tackle, they needed to be changed out from metric bolts to 3/8" course. The TC needs to get bolted to the flex, started motor bolted up. Needed new starter bolts, from metric to standard.

Still need to finish wiring in the new fuel injection harness and plug in every sensor harness.

And,The K&N FIPK for 4.3L did not need to get modified at all to fit on the V8

We also mounted the secondary trans cooler. Yes I know, I have some aligning to do... of the bumper cover and the cooler.



Cheers ~Mykk

Day 3. Sept 8th.

Just taking it easy and going slow. I have a few appointments today that are keeping me from completely dedicating myself to the truck today.

My hopes of just having the transmission mount slid forward and giving me the misaligned motor mounts were wrong. The trans was all the way back in the slot on the crossmember and I was about 1" from having the motor mount bolt holes line up.

So I went with the first idea that came to mind. Elongate the transmission crossmember hole even more so the entire rotating assembly can slide back enough to compensate for how far off the motor mounts were.



And it worked! The engine is now bolted down and sitting at the correct level.





It's funny looking at the V8 with the 4.3L intake & TB & accessorys... it looks like I still have the six cylinder in there.

Check out all that room I still have too.



Cheers ~Mykk

man its sure looking good cant wait till u fire her up.

It's Alive

http://www.youtube.com/watch?v=Yby9TFEfB7I

And still needs computer tuning before drivable

Cheers ~Mykk

After spending weeks with computer tuning, and not being able to resolve the drivabilty problems, missfires, lack of power and split BLMs from one bank to another.

It turns out the trucks original 6243 PCM & operating system couldn't support the L31 fuel injected, Vortec headed, Small block chevy V8.

I ordered up a 0411 PCM that is true to the L31 5.7L found in 2002 G-vans. The harnesses on the original 6243 are a direct plug-in to the 0411 with some slight modification to the indexing covers on the green plug of the harness.

The computer tune is a factory 2002 Express 1500 2wd 5.7L/4L60E... The 2004 Silverado features aren't 100% compatible with the 0411 PCM, the ignition switch, Oil pressure sending unit and ABS computer needed to get modified to work around the PCM. As well as a couple O2 sensor ref signal & feeds needed to get repinned to a different location in the plug.

The '02 G-van tune does still need to get modified for the engine internals.

Regardless, it runs a hell of a lot better and can finally drive itself down the street... and than some.

http://www.youtube.com/watch?v=VHlK5-K4Bdo

Cheers ~Mykk

where did you get the motor mounts from? are they oem?

The motor mounts and mount to frame brakets are for the V8's of this body style. Only an adapter plate was used to go from the Lsx V8 mounts to SBC