1994 OBS to LM7 swap, Am I missing anything?

Hey all, new member who needs help.
I have a 1994 silverado 2 door step side with a 350/TBI, 4L60E, 2 wheel drive.
I am looking to buy a LM7 5.3 to swap in and am having a bit of confusion. Will it be cheaper to keep the fuel injection or go with the carb conversion?

First off, I have been told that the 4L60E in my truck was the first year for the silverado's, so it has the old wiring harness that won't connect to the newer harness.

Also, I want to know if I make the 5.3 harness a stand alone, then what do I do with my original harness, and how do I make the trans work with the newer harness?

What I am thinking about doing, but don't know if it will work.
1st, I can buy the 5.3 and make it a stand alone harness and leave my truck harness hooked up to run the guages, and somehow convert the trans harness to the new style?

2nd, I could buy the carb conversion kit and get rid of the whole wiring harness issue with the 5.3 and rig the TPS sensor onto the carb so the 4L60E will still work.

I have about $1,500 to $2,000 to make this happen.
Here's what I figure i need to buy or address
5.3
motor mounts
headers
e-fans
DBW/throttle body or carb conversion
Wiring harness, original one and 5.3 harness
fuel system
I am removing the A/C

Thanks

welcome! im in he middle of a swap similar to yours. however mine is a 1996. i believe the carb vs efi option is really dependant upon yourself. IMO the efi is better because it gives yo more tuning capabilities and stuff. also just looks way better than an old school carb set up. the 4l60e will work fine and pretty easily. you need the spacer http://www.jegs.com/i/JEGS+Performan...01010/10002/-1 and the longer bolts http://www.jegs.com/i/JEGS-Performan...01011/10002/-1 then you would have to make the holes on the 5.3 flywheel longer with a dremel or something so they line up to the torque converter. i just did this last week and didn't have any issues.

the 5.3 harness should have all the plugs for the older trans. there might be a difference with the 94 trans. not sure if its the same as my 96. the original harness will control everything else but the engine so gauges abs etc.

read over the obs to lsx thread a few times. it took me a few times to understand everything especially if you haven't started yet. best thing to do is get started then gather the info you need on the step that your at. theres so much info out there and different opinions of different way to do the same thing you will overload yourself with info lol. but looks like you got the basics down. you can take a look at my build thread its pretty damn detailed if i do say so myself and pretty well documented on each step. this is my first swap but thanks to the guys on here i been able to do everyhting in my back yard with basic hand tools and a very small budget. also if you check out minime68s blazer build thread he may be able to help you a little better because your wiring and everything will be the same.

good luck with your build and keep us posted

Great info, thanks.
What do you mean about making the holes on the flywheel longer? As in widen the hole because they wont line up?

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Originally Posted by 94_OBS

Great info, thanks.
What do you mean about making the holes on the flywheel longer? As in widen the hole because they wont line up?

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yea. page 2. i just used a dremel and made them longer not wider. lined up perfectly. also make sure u take the tq converter off and line it up before u drop the engine in. learned that the hard way. lol

http://hotrodlane.cc/PDFFILES/Lisa%20Tahoe.pdf

Thanks for all the info, your build page is very specific. So can I just get a newer torque converter instead of deepening the holes on the flex plate? Also, what is S&P's website, I have looked and not sure if I found the right one?

www.hotrodlane.cc

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Originally Posted by RedHeartbeat

www.hotrodlane.cc

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what he said...IMO they are very overly priced. with a little research you can probably find the same part on jegs or summit way cheaper. but elongating the holes on the flywheel is very easy and pretty much free if you already have the part. i just used a dremmel and it took 15 mins. bolts lined up perfectly. i ordered my spacer from jegs for $40 and S&p wants $129. or something crazy like that.