Another Motor swap...V8 or V6

[Blackbeard44]

I LS swapped my K20 with a motor and trans with 120,000 miles on it, my daily driver truck is a 2001 silverado 5.3 thats got 390,000 on original motor and trans, I wouldnt worry about freshenin up a LS motor thats got less than 200k on it.

when I cruise at 55 and dont screw around passing people I get 20+mpg the motor is barely turning 1600 RPMs

 

[Tbone]

4wd or 2wd? Also what’s your gearing, tire and trans?

Good to hear on the longevity. Definitely much better than I expected!

 

[Grit dog]

New here and I'm at the point many of you have been before...the old mighty mouse popped out a few of her innards and said goodbye, so it's time for a swap.

Straight to the point. I want to drive this pickup and I'm determined to find a way to do it. She's been parked for two years and it's time to work on changing that.



Don't bother sugar coating it. If what I'm asking is bogus then just say it. I'm truly looking for your input of the two options.

You asked for perspective, so....
You have a broken toy that you "want" to drive again. You have a daily driver, you don't "need" one and it will still be a toy.
You're not wanting power, but you'll take it. You're concentrating on fuel mileage, so up pops the idea to put an Ecoboost in it. Idk whether that's been done before, but either you're basically God with a wrench, torch and computers, or this is a bogus (as you put it) option that is about as possible as Biden making a competent decision or even not schitting his Depends today...

You can slap another small block in it for, whatever, money isn't the issue if you're even considering the Ecoboost rabbit hole.
You can be a little different but normal and install a LS/OD combo. (Good for 14-15mpg tops in our 2001 5.3 Tahoe, won't get better in a square truck on 33s I think)
Either of these options gets you on the road and for, lets say $2500 ish tops, if you are not going custom, shiny, hotrod HP with either.

With an Ecoboost, lets say you get 5mpg better 20 vs 15, 19 vs 14 ish. You "might" break even on fuel savings 100-150k miles from now...might.
This isn't about mileage and saving money as there are 1,234 better choices than a squarebody if you are on a tight fuel budget.

1 of them is a 12V Cummins. If you want something that will actually increase mileage and add value to the truck when/if you sell it and is "different" and won't result in people looking at it and going "why is there a Ferd Ecoboost in a chevy square?" and then looking at you and trying to read whether you're deranged or just eccentric!
Now if you said a Grand National or Syclone engine, I'd be more inclined to think that would be really cool and also about 1000% easier.

Or a 4BT Cummins if you want mileage and still not be underpants outside your jeans type of weird.

Or this is your vision and you'll get a big thumbs up from me, if you end up fully functional Ecoboost drivetrain in an old Chevy!

 

[Grit dog]

I LS swapped my K20 with a motor and trans with 120,000 miles on it, my daily driver truck is a 2001 silverado 5.3 thats got 390,000 on original motor and trans, I wouldnt worry about freshenin up a LS motor thats got less than 200k on it.

when I cruise at 55 and dont screw around passing people I get 20+mpg the motor is barely turning 1600 RPMs

But what does it average for mpg?
Can't say I've seen any average mileage starting with a 2 come out of any of the LS powered trucks and SUVs I've owned or driven. Unless resetting the mpg-o-meter while going downhill.

 

[Blackbeard44]

I have never kept track of the mileage between fill ups, but I will next time I use the truck. I let it warm up for 20 minutes everytime before I leave, thats gonna knock it down some, my snowplow pushes alot of air, It can and does swallow the fuel when I work it, which is most of the time, I only noticed the 20mpg once when I drove 200 miles non stop in it and it barely took 10 gallons to top it off, and that was empty bed and no plow cruising at 50-55mph because there was tons of deer crossing the road.

edited for more content: my bone stock 01 silverado averages at about 13 MPG and the squarebody i feel beats it by alot, the sqarebody weighs about a ton less than it does.

 

[Tbone]

You asked for perspective, so....
You have a broken toy that you "want" to drive again. You have a daily driver, you don't "need" one and it will still be a toy.
You're not wanting power, but you'll take it. You're concentrating on fuel mileage, so up pops the idea to put an Ecoboost in it. Idk whether that's been done before, but either you're basically God with a wrench, torch and computers, or this is a bogus (as you put it) option that is about as possible as Biden making a competent decision or even not schitting his Depends today...

You can slap another small block in it for, whatever, money isn't the issue if you're even considering the Ecoboost rabbit hole.
You can be a little different but normal and install a LS/OD combo. (Good for 14-15mpg tops in our 2001 5.3 Tahoe, won't get better in a square truck on 33s I think)
Either of these options gets you on the road and for, lets say $2500 ish tops, if you are not going custom, shiny, hotrod HP with either.

With an Ecoboost, lets say you get 5mpg better 20 vs 15, 19 vs 14 ish. You "might" break even on fuel savings 100-150k miles from now...might.
This isn't about mileage and saving money as there are 1,234 better choices than a squarebody if you are on a tight fuel budget.

1 of them is a 12V Cummins. If you want something that will actually increase mileage and add value to the truck when/if you sell it and is "different" and won't result in people looking at it and going "why is there a Ferd Ecoboost in a chevy square?" and then looking at you and trying to read whether you're deranged or just eccentric!
Now if you said a Grand National or Syclone engine, I'd be more inclined to think that would be really cool and also about 1000% easier.

Or a 4BT Cummins if you want mileage and still not be underpants outside your jeans type of weird.

Or this is your vision and you'll get a big thumbs up from me, if you end up fully functional Ecoboost drivetrain in an old Chevy!

I really appreciate the input. I won’t say money is no objective because it has to be within reason. But I’ll also say I’m not on a penny pinching budget to limp this along. I love these old pickups. This one in particular was my first vehicle so it’s got a little more of a special spot for me. Hence, why I’d like to be able to drive it.

As for the Ecoboost, I’ve spent countless hours researching and talking with a few folks that have successfully done it. Two things normally go in common with them, lots of time and not much support. Couple folks have done it for very reasonable prices on their own and a couple others popped my eyes wide open at the no expense spared to make it work.

If I could get aftermarket support like you can GM stuff, I’d jump on it. I’ve been still considering it due to the proven platform but I just can’t find enough folks with enough know to start doing it.

I’ve always had a diesel and if there is one thing I’ve always missed when driving them, that good ol rumble from a gas motor and some good chambered mufflers.

So for this one I’ll probably stick to the LS swap. I mention the mpg solely due to the fact that I’d love to make these 80-200 mile weekend round trips without be concerned about bringing a bunch of fuel cans. It’s a toy like you said, and nobody wants to spend more time fueling up than actually playing!

Thanks again for the outside perspective. Sometimes you can have a solution in front of you and look right over it in a maze of other “possible” solutions. Only to have another’s outside view point out the, “it’s been right here all along” option that you should’ve been doing from the beginning.

 

[Hunter79764]

Sounds like you are along the road already, but should have added some more info. I've had 3 LS SUV's, all suburban length.
2001 2WD/5.3/loaded otherwise, made it to 300k before I thought I'd be better off replacing the long block instead of swapping lifters. Pulled engine had hatch marks in the bores and great oil pressure, replacement engine had been overheated I think and probably cracked the heads, as it drank coolant until I put some stop leak in and ran it another 40k before selling. Truck had 4WD stance and 285/70-16 All Terrains and got 14/17 city/highway with my wife's lead foot.
Next was 2004 Denali XL, 6.0/AWD full time, about 6000 lbs empty and I always carry a few hundred in tools and stuff. It got 12.5 lifetime average mainly going back and forth to work here in DFW, and would run 14-15 highway if I was easy with it. 240k on the stock engine when it wrecked, and I plan on pulling the 6.0 and putting it in my "New" 87 with the only change being cam and springs.
Wife currently drives a 2013 Denali XL, 6.2/AWD full time, 400hp factory. Drove it a few months, not long enough to get MPG baseline, then the DOD lifters failed and I replaced the valvetrain with a Stage 2 cam from Texas Speed. Should be closer to 480-490 hp now, the wife drives like it has that much, and we get an overall average of about 11.5. I did knock down nearly 18 the other day on a highway drive averaging about 65, that was unexpected. Of course that one is mid-grade or premium, so costs are still higher. It has almost 200k, no need for refreshing.
The 5.3 swapped into my Monte had about 150k, no freshening work besides a new water pump. I think I reused the exhaust gaskets even...

My advice if you want relatively simple, reliable, proven, powerful, and efficient for highway trips? 4.8 with a basic turbo and ~8 psi, 4L80e, and possibly a bigger gas tank. If you don't need the power, 5.3 with a tune

 

[Tbone]

My advice if you want relatively simple, reliable, proven, powerful, and efficient for highway trips? 4.8 with a basic turbo and ~8 psi, 4L80e, and possibly a bigger gas tank. If you don't need the power, 5.3 with a tune

I’ve tossed this idea around. I can’t seem to find many 4.8’s “local-ish” where I’m at. 5.3 are just about every where you turn. I’d love a turbo and then I start looking back to the SB and I remember how quickly it went from a drive to letting the ponies run every time it came out of the shop. Lol it sure put a grin on my face, but I paid to play! 300hp in that pickup will do plenty fine. But it’s always tempting for just a liiiitle more…

Going to look at a motor this weekend and I’ll see if I finally pull the trigger!

 

[Grit dog]

Well, it’ll be a cool swap, regardless of what you do! As long as your having fun with it, that’s what matters!

 

[Bextreme04]

Current motor was netting me 8.5mpg, carburetor setup. All 55mph county roads to and from work. It was dyno’d at 323hp to the wheel. That was through built TH350, 3.73, and 33’s. It was a fun motor that lasted me many years. Just never practical as a backup vehicle. Made two round trips to hunting camp with it few years back at a whopping 10mpg best over 400 miles round trips.

The same motor was ran in my ‘70 for few years and through a 4L80E and 4.10’s. It was getting me 11-13 mpg city. 17 on the hwy at 65-70. 2wd pickup with 28” tire.

I’ve ran two other 350’s, both in the 4wd ‘84 and they were 9-10mpg city engines. Best 13-14 on highway at 55-60.

So carbureted and without OD, not the best option for trying to conserve some fuel. I don’t mind paying for gas but I’d like to drive more than 200 miles between fill ups.

I’m highly contemplating the 5.3 with 4l60 or 4l80. I like the 80 for durability in stock form. And after doing much research there just isn’t the swap support aftermarket for an Ecoboost into anything.

On LS swaps at how many miles is everyone freshening up the motor? I’ve got it in the shop with nothing but time on my hands.

I wouldn't worry too much on freshening the motor up if it has less than 250k on it and has good compression. Pull the trans pan and see what the fluid and pan looks like, then give everything a good exterior clean and change all the gaskets(intake, valve cover, oil pan) and send it.

My 2011 5.3/6L80 is at 205k and the engine is still going strong. Transmission was rebuilt at 160k due to a failed torque converter. The 454/4L80e that was in the 97 K2500 Suburban I bought as a donor for my swap had 288,000 miles and still drove great. I'm rebuilding everything just on principal, but it probably would have gone in and driven for a few years as-is.