5.3/6.0 swap questions

[1984 t type]

Thinking about doing a swap and had a few questions.

First how many miles are ok for a good swap candidate? I don't want to rebuild the motor just drop it in and go.

Second does anyone know the difference in mpg's between the 6.0 and 5.3 motors ? I don't plan on doing any regular towing so I'm thinking 5.3 but if I see a good deal on a 6.0 I will go that route as long as I'm not giving up too many mpg's since that's the purpose of the swap.

And third, I'm sure I asked this question on here before but will I be giving up any mpg's going with a 700r4 over a 4l60e. I only ask because I have a freshly rebuilt 700

Thanks for your help guys
Posted via Mobile Device

[65Guy]

As far i know a 700r4 and a 4l60e are the same trans just the 4l60 is electronic.

[Clyde65]

The 6.0 isnt known for an economical motor, but they arent as bad as some.

The 5.3 can be squeezed and get pretty decent mileage.

700 and 4l60e are the same trans, only the e denotes it is electronically controlled.

[1984 t type]

Ok thanks looks like I'll stick with the 700 for now
Posted via Mobile Device

[Clyde65]

Have you seen the LS swap page? might check it out along with the build page that is in the same section, TONS! of info and we are all here to help if we can.

[1984 t type]

Yeah I'm strolling thru there now. There's so much info on this site, I'm all over the place
Posted via Mobile Device
Posted via Mobile Device

[clinebarger]

A 5.3 will do fine, I have a 04 5.3/4L60E in a 85 C20 suburban & averaging 17 mpg. & plenty of power, The only mods are a custom tune, K&N filter & intake tube & dual exhaust. As for the miles on the engine...Go for the lowest mile motor you can.

Maybe this will light a fire under your butt....

[BR3W CITY]

If you just want a functional engine, with better economy and power....something like you would put in a daily, or just a weekend cruiser..then IMO the 5.3/4l60e combo is right for you. They can also be had on the cheaper end for LS engines, and 4l60e are plentiful. I've had less than stellar experience with the 700r4, less so with the 4l60e, but any increase in power level may shorten the life of the trans.

The 6.0 will be the more expensive option, but also the largest displacement (read: hp/tq) and stoutest platform to start from on a performance build. That will cost you in the mileage department however. A 4l80e or built 60e (or oldschool trannies like the th350 and 400) is in order if you want to run a 6.0 and do any modding. Again, you lose some mpg, but it varies depending on the setup.

As for your initial question about mileage; its really more about condition. I would say 100k would be the cutoff that I would buy for a swap. At 100k in decent appearing condition, you most likely have a decent engine that will last you for a while...but be prepared to do regular maintenance and replace some wear parts fairly soon. Not expensive stuff, but it can add up. at under 60k you have a greater chance for a "fresher" engine, but junkyard engines ended up there for a reason. If you can find out how the car wrecked, or buy a whole clip. This will also give you easy access to small nuisance parts that can be tough to track down in a pinch.

I kind of rambled but hope it helped.

[1984 t type]

That deff helped br3w. And clinebarger fire lit. Where are you guys getting your engines and harnesses from ? There are places that sell them locally but to me for the amount of miles that most of them have the prices seem higher than what guys are saying they got there's for. I think these salvage yards are catching on to the fact that this is becoming a popular conversion in the hotrod community and marking up the prices just because they can. What's the average going rate on a 5.3 with harness and computer with under 100k miles
Posted via Mobile Device

[ls1nova71]

You've got alot of questions going on, so I'll just answer some. First I would find the lowest mileage engine you can. I've bought several complete pull outs in the 20k mile range for under 2000. That's motor, trans,wiring, pcm accessories, ext. Price does vary with where you live though.

As for transmission choice, I would sell the 700r4 and go 4l60e. To hook up a 700 you'll have to figure out how to hook up the TV cable, and it has to be right on or your trans won't live long. That said, you won't be able to use a DBW engine. You will also need to find a VSS for everything to function as it should. Some people run without them but they definitely help driveability.
As for the 6.0, they get worse mileage because of the 4l80 trans and bigger displacement. For a driver the 5.3 is the way to go.

Always try to get the most complete set up you can find. Tracking down little parts will make a cheap incomplete initial buy not such a bargain in the long run. Those little things that you think are cheap will buckle and dime you to death.

If going DBW be sure to get the TAC module, pedal and wiring between the two because mix matching those parts can cause trouble.
Posted via Mobile Device

[1984 t type]

I plan on sticking with the 700 for now at least, my trans guy built the snot out of it and he has done great work on my transmissions in my street cars so it will handle the added power of the 5.3, and as far as adjustment it will go straight to him for that also. I dont plan on using the dbw setup so if my motor is a dbw and I go to a cable intake would I need a harness from a cable operated truck or can it be modified ? Sorry for all the questions and thanks for the input guys.
Posted via Mobile Device

[softballnrd27]

You can mod your harness to work with DBC but there are only certain computers that have the driver for the DBC TB IAC. Look through the FAQ there are links to modding your own harness, I think LT1swap.com has some good info on it.

[5150.4.67]

I took a chance with a 5.3 with 121,000 miles for $500 including harness. I opened her up and was just amazed. The short block needed nothing. Crosshatching still visible. The valves needed touching up, but that was it!

[68GMCCustom]

Why not a 4.8? They are even cheaper.
Posted via Mobile Device

[1984 t type]

How would a 4.8 perform in a 3/4 ton 4x4 truck ? I'm not looking for high performance truck but I don't won't a slug either.
Posted via Mobile Device

[68GMCCustom]

ehh....yah..... with that much load you're probably better off with the torque of a 5.3.
The 4.8 has a shorter stroke and rev's quicker though and they sell dirt cheap.

[jacobs68]

hello I am new to this site and need a lot of help doing a 6.0, 4l80e swap I have a complete donor truck that runs and drives and is complete I had a few questions for my swap into a 1968 c10 , first the fuel lines I got the in line fuel pump and filter and I am going to use the factory tank with a return line in the sending unit, but I also have a return line on my lq4 fuel rail as well? any help?


2. how do I do the shift linkage ?

3. harness removal of the donor truck?

thanks

[Hart_Rod]

Originally Posted by jacobs68

hello I am new to this site and need a lot of help doing a 6.0, 4l80e swap I have a complete donor truck that runs and drives and is complete I had a few questions for my swap into a 1968 c10 , first the fuel lines I got the in line fuel pump and filter and I am going to use the factory tank with a return line in the sending unit, but I also have a return line on my lq4 fuel rail as well? any help?


2. how do I do the shift linkage ?

3. harness removal of the donor truck?

thanks

2. Lokar
3. Very carefully..... Check out LS1howto.com and LS1tech.com. Lots of information.