4.8 vs. 5.3, same truck and gearing...?

[00shortbox]

I'd go 6.0 if you could find one. I went from a 4.3 to a LS6 5.7 and am getting the same fuel mileage as the 4.3. And that's with no MAF and the fuel trims at +20%. Something is frigged up with my tune or MAF, won't run worth a crap with it plugged in for some reason.

[mopower440]

well, i kinda would like to go from the 4.8 to the 6.0 but afraid of the mileage. I know in this big extended cab 4x4 the 5.3 will get better mileage than the 4.8, but afraid the big 6.0 may get worse than the 4.8..? Also, i want the swap to be as cheap and painless as possble and dont you need more stuff to use the 6.0 than the 5.3, stuff like modding some of the wiring and different injectors or stuff?

[RS/SS 4.8]

As long as its the same year everyrhing should swap over. They are the same externally its the rotating assembly that changes.

[mopower440]

As long as its the same year everyrhing should swap over. They are the same externally its the rotating assembly that changes.

well, thats a problem, my truck is a 1999, they say the 1999-02 6.0 engine wont bolt up to my original 4l60e trans because the crank is longer or something on the 1999-02 6.0. They say to use a 2003 or newer 6.0 if i wanna keep my stock 4l60e trans, so would the newer 6.0 (2003-newer) still work in my 1999, meaning my stock wiring harness and all will hook up to all the 6.0 stuff?

[kerrige]

A 2003 6.0 long block will fit everything just fine although I would think that 60e would kick the bucket long before the 4.8

[RS/SS 4.8]

^^^x2. The intake will have to be from ur truck since its dbc and 03 up is dbw. Have fun with that 60e living behind it.

[mopower440]

A 2003 6.0 long block will fit everything just fine although I would think that 60e would kick the bucket long before the 4.8

I would have the 60e built up to handle it. May do the 6.0 swap instead of 5.3 then, just needs to be a 2003 to 06 to bolt to my 1999 4l60e right?

[RS/SS 4.8]

Yup

[TXSZ66AVLANCHE]

I went from a 4.8 to a 5.7 and my mpg (under normal driving) actually improved. Stock 4l60E with 127k has held up just fine, so far I've had the combo for 10k miles and beat on it daily.