Choice between 4.8 and 5.3

[1966Stepside]

Ok, so I have a choice of engines to buy. The one I had intended to buy was a '05 4.8. Now I have a choice to buy a '06 5.3. The 4.8 has 17k on it, and the 5.3 has 80k. I also believe the 5.3 has the variable displacement since it is an '06.

So, should I go with the 4.8 with lower miles, but also lower hp and mpg or the 5.3 with more miles and more hp and fuel mileage? I don't intend for this truck to be driven every day, but 2-3 times per week wouldn't be out of the question. Help me decide!!!
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[Clyde65]

I have the 4.8 4l60e in my 65. the only thing you would possibly gain from a stock 5.3 over the 4.8 is about 25 horse. that's it. mpg difference would be minuscule ( 1-2mpg lower on 5.3, maybe)

With mine, I am running somewhere around 300hp and that is more than plenty for me, it gets around 19-20 mpg on the highway, 14.5 or so city/mixed, starts every time and sounds fantastic.

[1966Stepside]

Originally Posted by Clyde65

I have the 4.8 4l60e in my 65. the only thing you would possibly gain from a stock 5.3 over the 4.8 is about 25 horse. that's it. mpg difference would be minuscule ( 1-2mpg lower on 5.3, maybe)

With mine, I am running somewhere around 300hp and that is more than plenty for me, it gets around 19-20 mpg on the highway, 14.5 or so city/mixed, starts every time and sounds fantastic.

I was checking the epa site last night, and the variable displacement actually gives an advantage to the 5.3 in the 1-2 mpg range. Thats in a stock silverado, of course
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[Clyde65]

I know the EPA said it, but I dont buy it myself. either way you will get marked better mileage than a NA small block, better starting and not to mention the cool factor.

Also your 2006 5.3 will probably have VVT and AFM on it. that would also attribute to increased mileage but maybe not increased driving pleasure.

[1966Stepside]

Originally Posted by Clyde65

I know the EPA said it, but I dont buy it myself. either way you will get marked better mileage than a NA small block, better starting and not to mention the cool factor.

Also your 2006 5.3 will probably have VVT and AFM on it. that would also attribute to increased mileage but maybe not increased driving pleasure.

And of course all the extras means more stuff to break
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[Clyde65]

TRue, if it were me, I would go with the 4.8. but my opinion is a little tainted too.

[1966Stepside]

I did find that it does not have Variable displacement
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[1966Stepside]

Originally Posted by Clyde65

TRue, if it were me, I would go with the 4.8. but my opinion is a little tainted too.

My only worry is that the 4.8 is underpowered. I have a 5.3 in my extended cab 4x4 sierra and sometimes i want more gas pedal. I test drove some 4.8 and could feel the difference. Also, i dont plan on keeping it stock for very long, and my understanding is that the same upgrade on both engines will give more results on the 5.3
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[Clyde65]

if you cam the 5.3 and a good tune, yes you can expect sizeable difference. I am talking about stock only.

If you came and drove mine, you would be impressed IMO, mine isnt anything special other than tune/headers and CA kit. but it boogies.

I also know mine isnt a 6.0, I have a friend that has a 6.0 in his camaro, holy crap that thing is fast.

Good luck, hell get what you want, sounds to me you already know which one you want and will get.

[Pop's C-10]

A 4.8 cammed would be diff..(most)everybody has cammed 5.3 & 6.0..

[Puropedo]

I have driven all kinds of GM trucks equipped with 4.8,5.3 and 6.0's, and let me tell you If I were to pick one of those it would definitely be the 5.3.

[1966Stepside]

I wanted a 5.3 to begin with, but the 4.8 was practically new and ata good price. Now that the 5.3 is also an option, I want to go the more practical route with the 4.8, but hp fever is tough to ignore
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[matthew20061]

I would go with a 5.3L hands down. The 4.8 is a great engine as well but if your going to all of the work to do a swap go with the 5.3L. I was very happy with the one I put in my 69' until I upgraded it to a 6.0L.

[usmcchevy]

I wanted a 5.3, but my 07 4.8 with only 30K on it came to me too cheap to pass up. Plan is to run it until it blows, then 5.3/6.0/6.2 time

Also you can get a 4.8 in a 3500 full size van or a Crew cab 4x4 truck and a 4.8 moves those just fine. With the size of our trucks, I think I'll be ok.

[harnalien]

Well whichever one you get, make sure it is a good engine. I've just been set back by about 2 months because the one i got has bad heads
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[1966Stepside]

I have a guarantee on the engines, so no worries there
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[Super73]

Ask your self this question (And answer it honestly): "Am I going to modify this motor or leave it stock?"

Answer no, buy the 4.8..

Answer yes, ask your self: "How far am I going to go with the modifications?"

Answered as bolt ons, you can go either way, but the 5.3 is going to give you more gains with the same parts.

Answered internals, IE Cam and possibly heads, you definitely want the 5.3 over the 4.8. The added displacement is going to help tame most any camshaft you put in there and will provide you better driveability than its little brother with the same mods.

Answered rotating assembly plus head/cam at some point, then it doesn't really matter. Yes the 4.8 comes with the short stroke crank but the blocks are the same. You could find a longer stroke crank next to nothing at a later date or if you are going to go 4" stroke someday it won't matter. But if you plan on going this route, get yourself a 6.0 for the simple fact that the 4.8/5.3 bore is small and really hinders head flow by shrouding the valve, killing power NA in comparison.

[1966Stepside]

Thanks for the input super73. Most likely cam, heads, intake, and then bolt ons to finish it off. May do the cam right away then get my tune. So it sounds like the 5.3 is my motor.
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[Super73]

Yes, the 5.3 will respond better to the cam and will be much more driveable with the longer stroke. More questions come up since you say you are going to go with a cam...

What are your goals with this combo?
What RPM are you willing to spin it to?
Are you wanting a TQ motor that falls off before 6K or something that has a little less TQ but will pull clean to 6,500?
What bolt ons are you planing for it? (Manufacture and dimensions [intake size/make headers])
Do you already have a cam in mind?
How big of a Stall are you planning on running?
What gear are you going to be running?
Tire size?
Whats the weight?


IMO a cam is the one of the most important parts of any combo. Picture it like this. You are a customer looking to have a business do a specif job for you. The cam basically the boss telling every one how to act at a finely tuned business. But if that boss is telling everyone at the business to do something that will produce a product you are not happy with, you will never get the results you wanted. It is important to explain exactly what you are looking for to the boss so he can tell his/her workers what to do producing the results you want.

Now, if that boss has the right idea but the wrong workers working for him (the bolt ons/gearing/converter) that goal again will never be reached even though the bosses best intentions were there. This is why planing a combo to work together is more important than most people think. The question you have to ask is do you want to put the boss before the workers, or do you want to put the workers before the boss?

In your case if you put the boss before the workers, you may have to fire/rehire workers to get your desired results because the boss is telling everyone what to do and he is not changing his mind. If you have good workers already, then you can interview some bosses and select the one that will run your current business the best. My point, I generally make cam selection only after I know what everything else will be. Don't get me wrong, there is going to be the possibility of a bad worker or two for the business, or the idea holder comes up with a better product requiring the company to change how they make it (IE new boss or workers), but that comes with the territory.

[1966Stepside]

I was thinking get the cam first since that will benefit from a custom tune more than the boltons would.

I want a streetable engine that makes its power between 1500 and 5.5k I havent started shopping yet so i dont have a cam in mind, but i know how I drive. Not building a racer, more of a cruiser. Decent acceleration but comfortable at highway speeds. Once i actually have the motor I'll do more reading and get everything i need.
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[Super73]

Personally I think you are going about it backwards. Putting a cam before the bolt ons is asking for less than stellar results.

How do you know the valve events you selected in that new cam shaft are going to work in harmony with the header diameter/tube length?

How about the intake, if you are going to change it is the cam going to be optimal for it?

When you change cyl heads, is it again going to be the right cam?

Even if you don't buy the bolt ons now and go with the cam/tune first, deciding what you are going to run before buying the cam will ensure your full combo will work well together. But once you make that decision, stick to it until you change the boss again.

An Engine is a sophisticated pump. Intake length and head port length / diameter can be tuned with Intake valve opening/closing points to optimize power. The same is said for exhaust port length, diameter, header diameter, primary length, collector length and the relationship exhaust valve opening. Then overlap of the cam etc.. With out knowing what the surrounding combo is, it will be extremely hard to pick the right cam for your goals.

[1966Stepside]

Oh, i see where the misunderstanding is coming from. I plan on doing all of the boltons and the cam before i mount the engine. I just meant i needed to do it all before i got the tune, but mostly because of the cam.
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[Super73]

I gotcha, that makes better sense..

So have you decided what headers/intake/heads/cam you are going to run?

[1966Stepside]

Originally Posted by Super73

I gotcha, that makes better sense..

So have you decided what headers/intake/heads/cam you are going to run?

Right now I'm deciding on the engine. I'll worry about the other stuff later. Thanks for all the input though.

[chevydog66]

6.0 but that's my .02