4.8/5.3 Vs. 6.0/6.2 – Which Is A Better Foundation To Build Upon

The “junkyard” LS engine is all of the rage these days, and for a good reason: the LS 4.8- and 5.3-liter engines are plentiful and certainly a popular choice for car enthusiasts as they can be picked up cheap from a salvage yard. In our area, it’s not uncommon to find these powerplants complete with accessories and a warranty for around $800. However, a 6.0-liter engine, in comparison, will easily go for double that amount of money since it’s the more desirable larger LS engine. And while the 4.8 or 5.3 might seem like a much better deal, you should think twice before buying and building one over a 6.0- or 6.2-liter engine. This might sound a little strange, but we talked to Bryan Neelen of Late Model Engines (LME) on why bigger is better. 

A few months ago, we reached out to Neelen to inquire about building a 5.3-liter engine for our 2000 Silverado; the plan was to punch our 5.3 out to a 5.7 with forged pistons, rods, an aftermarket crankshaft, and top it off with a ProCharger. And while this plan sounded like a solid one to us, Neelen was quick to ask why we were starting with a 5.3? We could tell that he was not entertained with our answer of, “Because it’s just sitting in the garage.” 

At this point, we started thinking, ‘are there really that many more advantages of going with a larger engine?’ Sure, everyone knows more cubic inches are better, but since we were planning on adding some boost, we knew we could throw more at it if needed. However, there are some excellent reasons to consider starting with a 6.0- or 6.2-liter engine that we didn’t think about.

The Cost of The Build

While you might think building a 6.0 or larger engine would cost more money, which it does, it’s a little misleading. Neelen said, “Let’s say you wanted to build a 1,000 horsepower 5.3. Even if you got the block for free, you could sell it and buy a used 6.0 block reasonably cheap. The cost of the internal components and machine work for any LS engine is the same. However, the larger engine will offer more power potential.” 

So what would be the actual cost difference between the two engines if all of the internals and machine work cost the same price? For that, we turned to eBay to get the price difference between a complete 5.3 and a 6.0 engine.  

Since we wanted to get the price of a 6.0 with rectangular port heads, we searched for the L76 6.0-liter and L92 6.2-liter engines. Much to our surprise, these two engines were in the same price range. We found an L76 priced at $2,999, with the least expensive L92 listed at $3,000. As you can imagine, prices for the 5.3 engines are all over the place. The cheapest we found was listed as a “Chevy LS 5.3 V8 engine” with no other information for $800. However, most of the other listings were between the $1,599-$2,300 mark, for a difference of about $1,500 between the 5.3 and 6.2 engines.

Things get a little more interesting if you’re planning on building a complete engine with an aftermarket crank, rods, and pistons. A good 5.3 block that’s been bake-blasted and checked for cracks will cost you $399 on eBay. We also found a newly-machined 6.0 block that was overbored for $900. That’s a difference of only $501. 

Cylinder Heads

When it comes to the cylinder head options with the LS, the 4.8-, 5.3-, and 5.7-liter blocks are very limited. Basically, you can only run a cathedral port head due to the bore size, but there is an exception: some aftermarket companies offer a small-bore rectangular port head, but they are expensive. 

So the only question here is, are the square ports better than the cathedrals? And according to Neelen, there’s a big difference. He said, “I’m a big believer in the LS3 heads over the cathedrals. We’ve done enough dyno testing, and we feel the LS3 cylinder head is a better performing head all the way around, especially in a boosted application. With the LS3 heads, you have a larger valve, with its 2.165-inch valve, than a cathedral port’s 2.00- or 2.02-inch valve.” The larger valves are a critical part of a boosted combination, and with a larger valve, you have the means to move air in and out of the engine more efficiently. 

Bigger Is Better

Unless you’re going after the 4.8 or 5.3 stock-bottom-end record, there’s no instance where fewer cubic inches is better. If you and your friend build an identical engine using the same components, compression ratio, and so on, but one is a 5.3-liter block, and the other is a 6.0-liter block, guess what? The larger engine is going to make more power due to its size. And if you add some boost to these two powerplants, you will have the same result. There’s a reason why people say there’s no substitute for cubic inches, and that’s because it’s true. 

Gen III Vs. Gen IV

When it comes to the Gen III engine versus a Gen IV, most will choose the IV due to the better internals. We have seen the Gen IV LS engines hold up to a lot of power in the past, but stronger internals is not the only advantage. The reluctor wheels between the two engines are also different, and this is good information to know no matter what type of LS engine you plan to build. 

The Gen III engine has a two-piece 24-tooth reluctor wheel. Unfortunately, these units can come apart on high horsepower/high RPM engines. To remedy this problem, LME makes a billet unit for the crank that can be welded on to prevent failure. However, if you start with a Gen IV crankshaft, there’s no need to worry about the reluctor wheels. Neelen said, “The 58-tooth reluctor on the Gen IV engines is an inherently better design. We will still tack them onto the crankshaft, but they will not separate like the Gen III two-piece design.”  

When Does A Smaller LS Make Sense?

There’s nothing wrong with the smaller LS, and let’s face it, not everyone will build an engine for competition use. These engines hold up exceptionally well, make good power, and are readily available from just about any local salvage yard. When combined with the fact that they are incredibly affordable, it’s the perfect platform for someone that wants to LS-swap a vehicle on a tight budget. And if it’s reliability you want, you can be certain that any LS engine is the perfect solution.  

While Neelen doesn’t think starting with a 4.8 or 5.3 block is the best gameplan in the world of competition –such as drag racing — he’s not opposed to building one. “If a customer wants us to assemble an engine using a 5.3-liter block for a street car, we will do it. It’s all the same steps for a larger cubic-inch assembly but with a different bore size. So we would go through and spec the pistons, dish volume, and bore size. An engine is an engine to us, and we will build anything as long as it’s a quality piece,” Neelen explained. 

At the end of the day, an enthusiast will build an engine that makes the most sense from their project. However, Neelen makes an excellent case about a 6.0- or 6.2-liter engine in competition use. And if you’re going to put thousands of dollars in an LS engine, you might as well spend a little more money and start with a 6.0-liter. With better power potential, rectangular port heads, and added access to larger cubic inches, you will undoubtedly benefit in the end. 

 

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About the author

Brian Havins

A gearhead for life, Brian is obsessed with all things fast. Banging gears, turning wrenches, and praying while spraying are just a few of his favorite things.
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