5.9 Cummins vs 5.3L? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Skunksmash · 08-23-2015, 12:01 AM

A buddy of mine is weighing the 5.9 cummins vs the 5.3L (or other LS). Guess if the 6.0 LS was a better choice, we'd go with that instead. He wants to put one of those in a K20. The K20 would be a lifted 4x4, so that might put the cummins ahead of the 5.3. Or would it?

So basically, if you were going to buy a k20 and you had the choice between an LS engine and the 5.9 cummins, which one would you choose? And why? What are all the pros and cons? The cummins is going to be a more expensive swap. But it seems to me that when it comes to adding power, which he's definitely going to want to do, the two engines are pretty much equal.

TwoFiftyShifter · 08-23-2015, 01:07 AM

Big cost difference... Maybe a turbo 5.3L is a good middle ground?

**mongocanfly** · 08-23-2015, 07:08 AM

I would go ls...no question about it... I have several buddies with diesels of all 3 big brands and they all have had to have very expensive repairs..they are better when they run but their very expensive to work on and the swap expense would be another thing. You can build big power out of a ls for not a lot of dollars.

86c20 · 08-23-2015, 08:13 PM

i would go 12v or 24v cummins. more the 12 do to is ez of work. it is as simple as a carb 350. if you can read a book and turn a wrench you can fix it. expensive to fix??? that is all relative in the name of power and longevity. now the real ? is who will be doing said work? if you are then its cheap if you are paying then its not. gas and efi can be vary costly as well. ecm harness trans ecm ect...ect...ect. both have good both have bad. if its just a mall show off go gas if its a weekend worrier go gas. if you are going to pull play hard or daily and what a little bit better mpg go diesel. and yes you can get high mpg out of a diesel. there is a guy with a 4b in a burb that gets almost 30 with ac and full of family.

lilpoindexter · 08-23-2015, 09:02 PM

Cummins.

tucsonjwt · 08-23-2015, 10:27 PM

Diesels are nice, but:

Hard to find good diesel mechanics, and when you do they are expensive.

Diesels have most of what gas engines have, plus expensive extra parts.

Diesels have cold weather start issues.

Diesels historically use more expensive diesel fuel (not now, but will return to being more expensive in the future.)

Having said that, my ideal truck would be a 12V Cummins in a crew cab 4WD.

andrewmp6 · 08-24-2015, 02:17 AM

Cummins will be a little harder to swap and more money to do so.The ls will be a little easier to swap if you buy all the swap parts.Up keep the diesel takes more oil and has to be changed twice a year and the filters are huge and pricey.Then you got the weight balance of the truck if its going off road the ls is a lot lighter.A 12 valve cummins is like 1500lbs vs the 600ish of a iron block ls will be.

Edahall · 08-24-2015, 02:08 PM

Depends a lot on the use of the truck. If he is going to be using it for a lot of very heavy towing, then go Cummins. The low rpm torque of the Cummins is nice when towing heavy loads. If he is not interested in shifting a manual transmission, go LS. It costs big bucks to build up a reliable automatic transmission behind a Cummins. As far as fuel economy I get mid 20's with my 3/4 4x4 square Suburban if I keep my speeds down.
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08-23-2015, 12:01 AM	#1
Skunksmash Registered User Join Date: Sep 2012 Location: TX Posts: 1,014	5.9 Cummins vs 5.3L? A buddy of mine is weighing the 5.9 cummins vs the 5.3L (or other LS). Guess if the 6.0 LS was a better choice, we'd go with that instead. He wants to put one of those in a K20. The K20 would be a lifted 4x4, so that might put the cummins ahead of the 5.3. Or would it? So basically, if you were going to buy a k20 and you had the choice between an LS engine and the 5.9 cummins, which one would you choose? And why? What are all the pros and cons? The cummins is going to be a more expensive swap. But it seems to me that when it comes to adding power, which he's definitely going to want to do, the two engines are pretty much equal.

08-23-2015, 01:07 AM	#2
TwoFiftyShifter Registered User Join Date: Nov 2008 Location: Gwinnett GA Posts: 1,803	Re: 5.9 Cummins vs 5.3L? Big cost difference... Maybe a turbo 5.3L is a good middle ground? __________________ 1982 K10 SWB 1987 V20 - Sold - Doh!

08-23-2015, 07:08 AM	#3
mongocanfly Post Whore Join Date: May 2015 Location: Alabama Posts: 14,671	Re: 5.9 Cummins vs 5.3L? I would go ls...no question about it... I have several buddies with diesels of all 3 big brands and they all have had to have very expensive repairs..they are better when they run but their very expensive to work on and the swap expense would be another thing. You can build big power out of a ls for not a lot of dollars.

08-23-2015, 08:13 PM	#4
86c20 Registered User Join Date: Mar 2012 Location: edgartown mass Posts: 852	Re: 5.9 Cummins vs 5.3L? i would go 12v or 24v cummins. more the 12 do to is ez of work. it is as simple as a carb 350. if you can read a book and turn a wrench you can fix it. expensive to fix??? that is all relative in the name of power and longevity. now the real ? is who will be doing said work? if you are then its cheap if you are paying then its not. gas and efi can be vary costly as well. ecm harness trans ecm ect...ect...ect. both have good both have bad. if its just a mall show off go gas if its a weekend worrier go gas. if you are going to pull play hard or daily and what a little bit better mpg go diesel. and yes you can get high mpg out of a diesel. there is a guy with a 4b in a burb that gets almost 30 with ac and full of family. __________________ 1986 c20 "the hillbilly" 350 sm465 3.42gears 21mpg at 70mph 1985 k30 "the ice cream truck from hell" no rust az truck 197-8??? c30 "ramp truck" 454 1978 monte carlo 350 350th with 2.73 gears. no rust. sc car

08-23-2015, 09:02 PM	#5
lilpoindexter Registered User Join Date: Sep 2010 Location: los angeles Posts: 1,134	Re: 5.9 Cummins vs 5.3L? Cummins.

08-23-2015, 10:27 PM	#6
tucsonjwt Registered User Join Date: Jul 2007 Location: Tucson, AZ Posts: 3,189	Re: 5.9 Cummins vs 5.3L? Diesels are nice, but: Hard to find good diesel mechanics, and when you do they are expensive. Diesels have most of what gas engines have, plus expensive extra parts. Diesels have cold weather start issues. Diesels historically use more expensive diesel fuel (not now, but will return to being more expensive in the future.) Having said that, my ideal truck would be a 12V Cummins in a crew cab 4WD.

08-24-2015, 02:17 AM	#7
andrewmp6 Registered User Join Date: Jan 2009 Location: Louisville,Ky Posts: 5,811	Re: 5.9 Cummins vs 5.3L? Cummins will be a little harder to swap and more money to do so.The ls will be a little easier to swap if you buy all the swap parts.Up keep the diesel takes more oil and has to be changed twice a year and the filters are huge and pricey.Then you got the weight balance of the truck if its going off road the ls is a lot lighter.A 12 valve cummins is like 1500lbs vs the 600ish of a iron block ls will be.

08-24-2015, 02:08 PM	#8
Edahall Registered User Join Date: May 2011 Location: Goliad, TX Posts: 672	Re: 5.9 Cummins vs 5.3L? Depends a lot on the use of the truck. If he is going to be using it for a lot of very heavy towing, then go Cummins. The low rpm torque of the Cummins is nice when towing heavy loads. If he is not interested in shifting a manual transmission, go LS. It costs big bucks to build up a reliable automatic transmission behind a Cummins. As far as fuel economy I get mid 20's with my 3/4 4x4 square Suburban if I keep my speeds down. Posted via Mobile Device



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