So ill start out with the history

bought the truck with 260k miles on it, truck was in amazing shape, looked like it had about 50k miles and prev owner said the engine and trans had been replaced with a junkyard swap.

So i drove it about 3k and did the first oil change. The engine oil was sludge and the oil filter weighed a few pounds and was pouring out slime..

So i put seafom in the oil, intake, gas and drove it a 1k miles or so, did a engine flush with that de-gunk plus the seafoam that was already in it. and i have done the oil change with seafoam and de-gunk plus full synthetic every 2k miles since then and it has gotten way better but its burning oil now and you can kind of tell from the exhaust sometimes that its coming out. The first time i seafoamed it, it poured out black crud from the exhasust pipes

anyways i drive it everyday and have been on a few 1000 mile trips and its very reliable, pretty quick, and a fun truck


I just got a mustang coupe that I want to put a chevy motor in, would my best bet be replace this motor in the truck with another just stock 5.3 or 4.8 and put the motor in my truck in the mustang after a rebuild? that way they both have good new motors? if I put something else in the truck, will doing high compression pistons get me higher gas mileage in either one? anyone do any MPG builds on a 5.3 or 4.8 in the silverados?

any advise, not sure how in depth i wanna go with the mustang. I just want it to have decent power which i know a cam intake 5.3 will give me

but doing an 11:1 build or so give me better mpg?

ive seen ls1 trans ams and vettes see 27-30 mpg i want to achieve the same in my light weight coupe with a smaller displacement motor

 

If your doin a Fox body ive seen a few cammed 5.3 and 6.0s with automagics getting high 20s in mpg.

Tuning is goin to be your mpg getter along with the right setup. 11:1 will net more power across the board of course, but more power=more fuel for the extra air. But i dont see it hurting with that light of a car.

If it were me, i would get a newer/cleaner engine for the truck and put the old truck engine in the car after a breakdown and inspection.

 

If it were me, i would get a newer/cleaner engine for the truck and put the old truck engine in the car after a breakdown and inspection.

^^

 

Just installed an LS1 in my dads 2000 that came with a 4.8 from the factory. It was the best mod hands down and we got the complete long block for $800 with half the miles of his old 4.8 engine. I would look into something like that, if your going to swap motors it doesnt take any extra time to swap to a bigger motor while your at it and your gas mileage wont suffer much if you can keep your foot out of it.

 

If I go to a 6.0, do I need a new ecm or can the 4.8 ecm be reprogrammed?

Does anything else need to be changed?

Thanks in advance,

 

For 6.0 swap info do a search on here, there are plenty of threads covering the topic. Or PM me if you have any specific questions and I would be happy to help, just dont want to hijack this guys thread. In short the 4.8 PCM can be reprogrammed and nothing else HAS to change in order to do the swap although there may be things you want to do while you have the motor out and it is accessable. Well I guess there is one other thing.....make sure you remove the spacer on the back of the crank if your using a 60e, if your installing an 80e with the 6.0 then dont worry about it.

OP, like I said above, I would upgrade the motor in your truck then do what Jonathan said and rebuild your truck motor for your car. Then you would have two vehicles that would be fun to drive and reliable.

 

cheaper to go with what you got is a motto i usually go by when it comes to budget builds.

so i would get me a low mileage 5.3 truck. 4.8 is same block as 5.3. youll see 4.8/5.3 stamped on it. since it needs rebuild and 5.3s have been known to be bored out to a 5.7 bore and 5.7 internals swapped in, i would turn it into an iron block 5.7. more cubes and cheaper than 6.0. a 228 cam, 3200 stall, truck intake for budget or ls6 intake, same tb and computer, some 3.73s and you should have a pretty quick, lighweight, and still mpg friendly ride. if i can help with any other advice or 2nd opinion, just pm. good luck with your project and GOD Bless....rob

 

Thanks for the input guys! I have been thinking about swapping the 6.0 in my truck, i Just didnt want to see those horrible 11-13 mpg figures that the 2500 sees. I average 14.5 in the city and about 17-21 on the highway the difference between 1900rpm (70) and 2200rpm (80) makes a HUGE difference on my MPG

I would like a little more power when hauling in my truck, and i did think about the 6.0 and the 6L80e from a 06 or so wrecked something.

Also if i did take the 4.8 out of my truck and put in my car i would not reuse the 4l60e, it would be a t5 or t56 not wanting a full dragster like my last coupe, itll be more of a street car doing 65mph at 3400rpm sucks lol

 

Check this car out with a 4.8..

Potential they do have

first 4 8 stock bottom in the 8s - YouTube

 

My dad lost 1 MPG on the highway (gets about 21 now) and city MPG stayed the same when swapping to the Ls1 from the 4.8 after a retune from Justin at Black Bear Performance. This is in an extended cab truck as well.