5.7 vortec vs 5.3l or 6.0 swap

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90west

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I’m sure this has been discussed but my question is I have a 97 k1500 ccsb with a 5.7 vortec and a 4l60e the truck is currently sitting on 33’s.
The truck runs great I’ve had the truck for 18 years now but I’m starting a mobile mechanics Business primarily working on powersports equipment and with the price of used trucks it’s not in the budget to buy a work truck so I want to build this truck for towing sxs’s back to the shop problem is it’s a bit of a dog, sry for the long intro but I feel information is key in this scenario.

1- is it worth hopping up the 5.7
2- is it worth swapping in a Ls based engine

The issue comes down to time and cost because I really don’t want to swap the engine just because I know I’ll pull it and it will end up sitting due to the shear amount of customer work I currently have any ideas would be greatly appreciated
 

stutaeng

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Agree with above. If engine runs good, no reason to mess with it. You need some 4.10s or 4.56s...

Now, did you say a 1500 "Crew Cab"? Is that a conversion? A 4L80e swap would be more appropriate for a heavy truck like yours...:rolleyes:

Edit: How much are you towing anyway? Throw a 14 bolt 9.5" 6 lug rear axle in the swap bucket list...
 
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90west

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No issue re gearing the truck is going to get a sas soon with a Dana 44 front problem is it’s gonna end up with up with 35’s minimum because where I go ends up being very remote on some of these ranches here in south texas
 

MrPink

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With going SAS and 35's, at minimum i'd recommend 4.88 gears. The chart is a good guide, however it is based on 65mph not 70-75.

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TreeGeared

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For towing I would be against the big tires and lift. Extra drag and torque requirements will not help with towing.

As for your original question on engines. I have a k2500 with the 5.7 vortec, 4L80E and 4.11 gears. Tows very well with 265/71/16 tires. If you replicated that I would think you would be very happy towing a dual axle trailer with side by sides.

My other truck is a k2500 6.0 LS, NV4500 and 3.73 gears. 235/85/16 Tires. Not apples to apples but also tows very well. The 5.7 seems to be better at the lower speeds and taking off with torque. Probably due to the lower gears. The LS "feels" like it has better torque and pickup above 3500 rpm.

If your 5.7 is in good condition it is probably not worth the work and expense of an LS swap. Gear it properly and carefully consider your tire size and you should have a nice tow rig.
 

0xDEADBEEF

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Those charts don't take into account load on the engine either. I'd run lower gears in a 5000 lb truck towing a 5000lb trailer than I would in a 3500 lb Jeep with just big mudders even if the chart says they would be the same.
 
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