5.3 or 6.0 Conversion

[SS Delux]

I am looking into doing a 5.3 or 6.0 conversion on my truck, what kind of gas mileage are you guys getting ? What is a good price for just a motor ? are high mileage motors a concern ?

[N2TRUX]

I hear all kinds of wild MPG claims, but I am a bit skeptical. I get an average of 17 mpg out of 5.3's in my late model trucks. Unless a tune makes your milage improve dramatically, I wouldn't expect much more.

If no one replies here you might try the LSx forum.

[veinbar]

Originally Posted by N2TRUX

I hear all kinds of wild MPG claims, but I am a bit skeptical. I get an average of 17 mpg out of 5.3's in my late model trucks. Unless a tune makes your milage improve dramatically, I wouldn't expect much more.

If no one replies here you might try the LSx forum.

If 17 mpg is the average one can expect from this swap then why is it so popular? Would this average be for a carbureted or fuel injected LS? I too have considered this swap, but I'm weighing the cost/benefit ratio...

[camshaftgsxr]

Originally Posted by veinbar

If 17 mpg is the average one can expect from this swap then why is it so popular? Would this average be for a carbureted or fuel injected LS? I too have considered this swap, but I'm weighing the cost/benefit ratio...

people do get better mileage but for the most part they are very smooth running engines and have the potential to make a lot of power. that and you can generally pick up a running low mileage 5.3 for $1000 whereas a rusty ol 350 would cost the same of more after a rebuild.

[Clyde65]

I average around 15 in the city and 19 on the highway. I did my swap because...

1. my motor and trans was real tired and ready for rebuild anyway.
2. I got a motor and trans for around $1200. with all acc.
3. I had NO IDEA what I was getting into.
4. I was only getting 8MPG with my old 350/400 anyway.

[veinbar]

Originally Posted by Clyde65

I average around 15 in the city and 19 on the highway. I did my swap because...

1. my motor and trans was real tired and ready for rebuild anyway.
2. I got a motor and trans for around $1200. with all acc.
3. I had NO IDEA what I was getting into.
4. I was only getting 8MPG with my old 350/400 anyway.

Can you even guess what you spent on said conversion? My "stockish" 350 gets 12 mpg in town and 16 hwy. I have averaged higher on the highway, but I suspect I had perfect conditions (empty bed, stiff tail wind, light foot). I would love to swap in a 5.3L but the cost seems overwhelming. Am I way off?

[N2TRUX]

Originally Posted by veinbar

If 17 mpg is the average one can expect from this swap then why is it so popular? Would this average be for a carbureted or fuel injected LS? I too have considered this swap, but I'm weighing the cost/benefit ratio...

That average would be for a bone stock 5.3 in my late model truck. Why is it popular? Because there are a gazillion LSx motors out there that can be had for very little money. They are very reliable, long lasting and can produce a LOT of power if you want them to.

If I were going to do an LSx swap, I would find a 6.2L . They are the best bang for the buck even if you pay a bit more for them.

[camshaftgsxr]

Originally Posted by N2TRUX

That average would be for a bone stock 5.3 in my late model truck. Why is it popular? Because there are a gazillion LSx motors out there that can be had for very little money. They are very reliable, long lasting and can produce a LOT of power if you want them to.

If I were going to do an LSx swap, I would find a 6.2L . They are the best bang for the buck even if you pay a bit more for them.

another thing is the "cool" factor, my girlfriends dad has a 6.0 cadillac h/o motor with a tune and a cam pushing 450hp (enough to beat a gt mustang in a 64 panel truck)

[rayfinseats]

I have heard of 5.3 EFI motors going for $500 with computer and wiring harness from junkyards. I'm sure the price will go up once they catch on to us. I hear they make great horsepower. HOT ROD mag claims they got 1200 HP from a stock 4.3 (4.8?) V8 with dual turbos...hmmmmmm

I think if you could pick up a 5.3 for $500 it would be worth it. ANYONE running a 5.3 with carb?

[N2TRUX]

Actually the prices are going down for the average 5.3. Keep in mind they have been out for several years and came in hundreds of thousands of GM trucks and vans. If you want the more desirable 6.0 or especially the 6.2 you will pay more, but those can be found too.

With new heads, cam, and intake you can have 500 hp that will run on pump gas all day long. Try that with a carbed motor.

[pwtr02ss]

lsx motors are just cool all the way around. the sky is the limit on what you can spend on the swap. It also depends on your skills and how much you can do yourself verses what you will have to buy.

[camshaftgsxr]

Originally Posted by rayfinseats

I have heard of 5.3 EFI motors going for $500 with computer and wiring harness from junkyards. I'm sure the price will go up once they catch on to us. I hear they make great horsepower. HOT ROD mag claims they got 1200 HP from a stock 4.3 (4.8?) V8 with dual turbos...hmmmmmm

I think if you could pick up a 5.3 for $500 it would be worth it. ANYONE running a 5.3 with carb?

speaking of, there is one just like that already pulled near me for 500... wish i had 500 lol.

and yeah 4.8's and 5.3s make a ton of power boosted, something about the short stroke

[veinbar]

Originally Posted by camshaftgsxr

speaking of, there is one just like that already pulled near me for 500... wish i had 500 lol.

and yeah 4.8's and 5.3s make a ton of power boosted, something about the short stroke

aren't ls motors small bore / long stroke?

[softballnrd27]

The potential for power from these motors are much higher than your average GEN I SBC. You can take a stock 6.0l block, crank, forged rods and pistons and get over 1000rwhp. I haven't seen too many stock 350 blocks or cranks that can handle that abuse. You can squeeze 10-12psi of boost on a completely stock motor and make 500-650 rwhp. Depending on your driving style you should be able to get a little better gas mileage than what the 5.3 or 6.0 came out of because you can eliminate alot of unneccesary smog stuff.

[softballnrd27]

Most of them are 3.662" stroke

[SS Delux]

Wow great response, the reason im looking at this swap is because the 4.3L V6 I have gets like 10 mpg on the highway. I have never rebuilt and engine before and I want to do something that will get me the greatest bang for my buck. Are high km motors a problem ? what else should I watch out for ?

[pumpgas]

Originally Posted by veinbar

aren't ls motors small bore / long stroke?

Not really....5.3L is 3.8XX bore by 3.622 stroke and makes 325ci
LS1 is 3.90X bore by 3.622 stroke and makes 346ci
6.0L is 4" bore by 3.622 stroke and makes 364ci
6.2L is 4.070 bore by 3.622 stroke and makes 376ci

All LS based engines besides the LS7 and 4.8L have 3.622 stroke cranks but half way through 04 GM changed reluctor wheels from 24 tooth to 58.

[SS Delux]

I have a lead on a 5.3 wi approx 90000 km (56000 mi) for $100. It has no intake and possibly no computer, it also sat outside and got water in the intake runners. Worth the money ?

[pumpgas]

Originally Posted by SS Delux

I have a lead on a 5.3 wi approx 90000 km (56000 mi) for $100. It has no intake and possibly no computer, it also sat outside and got water in the intake runners. Worth the money ?

No it needs a complete rebuild and by the time u do that it'll cost way more than buying a complete good running low miler.

[Clyde65]

I only have the 4.8/4l60e in mine. no cam or nothing, the 6.0's will run you well over $1700.00 for the engine and ecm/harness, those are great for HP/TQ but hurt the wallet if you want to do a budget build. the 4.8/5.3 motors will put out a respectable 325-400 horse with a good tune and bolt ons. I only wanted the cool and reliability with the economy of the FI, I got exactly what I wanted. Plenty of power for highway use.

Mind the mileage on some of these "deals" too, over 150K and a rebuild will be in order. these motors. properly maintained, can go well over 200K ( my BIL had a truck with the 5.3 with 296K when he traded it in cuz it needed extensive driveline repairs ( not motor)

I have in mine probably 3500, but know that is counting stuff I had to do twice because I didnt wait for information or it just wasnt there, it definitely is here now.

So a quick run down, $500 motor, $750 aftermarket harness and PCM tune, 250 mounts/brackets, $150 fuel pump/lines, 150 misc ( ds shortening/fittings/ fluids etc.
so for around $1500 you too could have an LS motor, oh btw, for the economy, an OD trans is required. add at least $800

[SS Delux]

What about running my origional NP A833 overdrive tranny ? think the gas mileage would be the same ? worse ? all in all not a good deal on the $100 motor ?

[usmcchevy]

Swap cost can be kept down. I'll have less than 3K in my swap when complete. Granted I currently only have a 4.8, but there is a reason I wanted to have the 4l80e vs. a 4L60e

LS swap cost FAQ:

http://67-72chevytrucks.com/vboard/s...d.php?t=473560

LEEVON has the NP trans mounted to a LS, post #32:

http://67-72chevytrucks.com/vboard/s...=412159&page=2

[softballnrd27]

You can rebuild the stock shortblock for fairly cheap depending on how bad the cylinders are. You should be able to find a running 5.3 for under $750

[Psycho71]

I see the numbers people are getting out of their LS swaps, and they are impressive. I wonder though....What does the torque curve look like on these motors? They are obviously working good for the "hotrod", and even the fuel economy minded crowd. But I wonder how they'd work for someone looking to swap a stock(ish) 5.3l into a heavy 4x4 burb with big tires on it?

[JuicyJ]

I have seen ls engines here for sale on craigslist for under 1k with the trans and harness. I plan on doing a ls swap on my truck and I would love a 6.0 but I will take 5.3. I know the 6.0 are more expensive but worth it.