6.0/4.80e or 5.3/4l80e?

Engine swap is the big goal for the summer. For awhile i was definitely leaning towards the 6.0/4l80e. This will be going in my 94 z71, 12" lift, 38"s, 20", 4.88s (eventually to be 15" lift, 40"s, 22", 14 bolt and 5.13s). Lately I have been considering just looking for a 5.3 and a 4l80e given that 5.3's can be had so incredibly dirt cheap. I know the 6.0 isnt much more, but basically to get and lightly mod a 5.3 would be about what the 6.0 would cost, and hopefully mileage would be slightly better. I know with the 38"s im already far beyond "good" mileage, thats pretty obvious. However my thinking is that by finding a 5.3 real cheap, maybe throwing a cam, headers and some light head work into it along with a tune and a few other basic things, I could get all the "swap" work done converting from the 94 to the GEN III system (i will also be doing the 94 to 95+ dash swap as well). Once the whole swap is done, acquiring a block to build a 408 could be a longer term project and when the big engine was ready, it would be much simpler given that it would only require really pulling the 5.3 and dropping in the 408. I know of one guy putting down around 18ish mpg on the freeway with a 5.3 in his OBS on 38s, and the 5.3 already is a significant power gain over my current slightly tired 120k mile old 350 TBI.


thoughts? I'm thinking of doing this assuming I can find a good condition 5.3 complete with lower-ish miles in the sub $750 range, which seems to be doable around here.

thanks

nothing wrong with the 5.3. However a $750 motor would have higher miles, or be '' imperfect.'' Personally, If I was in your shoes, I would save up for a built motor. like a forged 11.0CR 408ci with a nasty cam. the 4l80e is going to eat allot of the power the 5.3 makes. I think when it comes to motor and cam swaps, go big the first time. unless its free, or dirt cheap.

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Originally Posted by ff_jeff

nothing wrong with the 5.3. However a $750 motor would have higher miles, or be '' imperfect.'' Personally, If I was in your shoes, I would save up for a built motor. like a forged 11.0CR 408ci with a nasty cam. the 4l80e is going to eat allot of the power the 5.3 makes. I think when it comes to motor and cam swaps, go big the first time. unless its free, or dirt cheap.

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basically i would only go with the 5.3 if i do indeed find solid one for dirt cheap compared to the 6.0s that are available. the 80e sucking power from the 5.3 was my other concern as well, hopefully it would still be a massive improvement over my TBI

I run 38s under my 1990 truck with kit body. I got rid of the tbi and th400. it is a bi difference. I am only seeing 14.8 mpg average but my truck is a brick and a half and running bias plymudders. it is really light though.

I hope get better mpg when i switch to radials with a higher psi.

still going to be running 38.5s though.

so kdog you are pulling down ~15mpg with the 6.0 in there?