6.2L Wiring Hookup??? Confused

[6600DURAMAX]

Man I am so new to this idea I dont even know where to start. It has crossed my mind for a while now to drop in a LS so I can just jump in the truck and drive. I came arcoss this Craiglist ad for new 6.2L motors that put out 425 horse or so. The guy says they are complete from the intake to coils to pan everything besides wiring and accessories. So here is the question

1. What type of wiring would I need to hook this up in my 71 ?
2. Can I use my current TH400
3. I think I would need a high pressure fuel pump instead of my Holley Blue
4. Do I need an ECM?? From what??

I have seen the MSD 6010 boxes but those are for LS motors with carbs this is fuel injected

Man so many questions

[BR3W CITY]

Originally Posted by 6600DURAMAX

Man I am so new to this idea I dont even know where to start. It has crossed my mind for a while now to drop in a LS so I can just jump in the truck and drive. I came arcoss this Craiglist ad for new 6.2L motors that put out 425 horse or so. The guy says they are complete from the intake to coils to pan everything besides wiring and accessories. So here is the question

1. What type of wiring would I need to hook this up in my 71 ?
2. Can I use my current TH400
3. I think I would need a high pressure fuel pump instead of my Holley Blue
4. Do I need an ECM?? From what??

I have seen the MSD 6010 boxes but those are for LS motors with carbs this is fuel injected

Man so many questions

1. having a custom harness made will be the most "plug and play" method. I had 4 wires to actually terminate, everything else was molex plugs.
2. Yes you can, let the wiring company you choose know that and they will eliminate the extra sections from the harness.
3. You will need a high pressure electronic pump, the 255lph pumps are cheap and plentiful. You will want to change out any rubber line for FI line or braided, as the regular stuff will bulge and or leak under that pressure.
4. Yep. You would want to ideally find the ECM from that same year and configuratoin (i.e. v8 w automatic). IIRC that engine may be DBW, so you may need to get the dbw pedal and tac to match also, or convert to DBC.

[6600DURAMAX]

Thanks BR3W

The motor I was looking at is a new Crate Motor, not a vehicle drop out so that is why I am confused about the ECM.
1. Are there companies that sell the wiring, ECM, pedal and all?
2. Will the TH400 just bolt up or do I need an adapter plate for the bellhousing
3. Is the 225LPH an in tank pump? Might have to run a fuel cell instead of my behind the seat tank if thats the case.

[66ChevyMax]

GM sells a ecm/wiring harness package made just for swaps.

Originally Posted by 6600DURAMAX

Thanks BR3W

The motor I was looking at is a new Crate Motor, not a vehicle drop out so that is why I am confused about the ECM.
1. Are there companies that sell the wiring, ECM, pedal and all?
2. Will the TH400 just bolt up or do I need an adapter plate for the bellhousing
3. Is the 225LPH an in tank pump? Might have to run a fuel cell instead of my behind the seat tank if thats the case.

[BR3W CITY]

Do you have a link to the motor, or does it say anything about Drive By Wire or a Cable Throttle body?

I don't think anyone sells all the dbw stuff as a setup, since its so dependent on specifics. Some of the companies may source an ECM for you, keep in mind you will need to have it flashed for your engine and to unlock VATS and remove emissions. I suggest getting a dyno tune as well, but its not needed to get her on the road.

255's are available either in -tank or in-line. Personally I would get rid of the death trap tank and use a fuel cell, it makes things easier and no gas fumes.



How's the leg room in your 71? I was looking at a 72 4x4 for a daily, but I'm a little concerned since the cab on my 66 feels small on room.

[usmcchevy]

6.2 is going to be DBW unless a aftermarket cable throttle body is installed. GEN IV engines do not use a TAC so no worries there, just need the gas pedal which from what I've read isn't nearly as fussy as the GEN III stuff. You can get a pedal from LoKar if you want. You can use your TH 400 trans,take a look in the LSx FAQ at the top of this page. I'm also using the Walbro 255, inline flavor. For the ECM and wiring, speartech, howell and GM among others will make you a new harness or convert a factory one. Check car-part.com for the ECM.

[Mr. 250r]

not to steal the thread but as far as the gas lines go my stock 91 lines are either all metal or stainless braided is that okay to use?

[BR3W CITY]

Originally Posted by usmcchevy

6.2 is going to be DBW unless a aftermarket cable throttle body is installed. GEN IV engines do not use a TAC so no worries there, just need the gas pedal which from what I've read isn't nearly as fussy as the GEN III stuff. You can get a pedal from LoKar if you want. You can use your TH 400 trans,take a look in the LSx FAQ at the top of this page. I'm also using the Walbro 255, inline flavor. For the ECM and wiring, speartech, howell and GM among others will make you a new harness or convert a factory one. Check car-part.com for the ECM.

Thats a good point usm, forgot the 6.2 didn't start til 07.
my harness was from fuelinjectionconnection, came with a new fuse box and custom setup for what I was running. I did have one wrong pigtail (it was my fault) and he sent one out for free overnight. I can't complain.


Mr 250r, your steel and braided lines should be just fine assuming they are at least 3/8 for feed. And fwiw, make sure its all steel line....my truck was redone by the po and had some ALuminum supply line...fine for 12psi but leaks like a sieve at 50psi.

[66ChevyMax]

Check GM performance part #19201861

Originally Posted by 6600DURAMAX

Thanks BR3W

The motor I was looking at is a new Crate Motor, not a vehicle drop out so that is why I am confused about the ECM.
1. Are there companies that sell the wiring, ECM, pedal and all?

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