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The Weight Of 48 LS & LT-Based Engines

What is the weight of an LS or LT-based engine? In this blog, we’ve researched the fully dressed, long block, and short block weight for 48 different engine types produced in the past 25 years. First, let’s start with a quick answer:

The weight of a fully dressed LS or LT-based engine lies between 418 – 610 lbs. An LS/LT long block weighs 260 – 545 lbs, and a short block weighs 106 – 256 lbs. The three largest factors that influence the weight are the engine’s size, the type of transmission, and whether It’s an aluminum or cast-iron block.

However, this summary doesn’t tell the whole story. In the table below, we’ve outlined the 48 different engines. Wherever possible, we’ve also added the difference between an engine with a manual or automatic transmission.

The Weight Of 48 LS & LT-Based Engines

Before you read the table below, it’s important to know how we did our research. Let it be clear that we didn’t buy all 48 engines and put them on a scale. Instead, we spend two days reading forums and finding official documentation that Chevy, GM, or well-known tuners provided.

While doing our research, we found that, in general, the fully dressed weight of the engines is quite well documented on the different forums. Also, many people on these forums did indeed take the time to take out the engine and weigh it. We considered these to be quite good sources.

The weight of the long blocks and the short blocks was a bit more difficult to find out. The numbers in these columns are best regarded as ‘best estimates.’ Many people on the forums that we researched don’t have a long block or short block engines (most are fully dressed), making the data scarce.

When we found a reliable estimate, we copied this estimate to other similar engines if no other data were available. For example, the size and the use of materials in the LQ4 and LQ9 are very similar. Data on the LQ4 was available, and data wasn’t available for the LQ9 long and short blocks. Therefore, we copied the results, given that they are the best estimate we could get.

NameFully Dressed Weight (lbs)Long block (lbs)Short block (lbs)Production Years
LS1 (automatic)457.63901061997-05
LS1 (manual)497.23901061997-05
LR45204301751999-07
LM75204301751999-07
LQ45204702161999-08
LS6497.24201062001-05
L595204301752002-07
LQ95204702162002-07
LM45204301752003-04
LS2 (automatic)442.64001062005–07,09
LS2 (manual)482.24001062005–07,09
L335204301752005-08
LH65204301752005-09
LS4478290x2005-09
LS74543841072006-15
L92418x1102007-08
L76450360x2007-09
LY2355260x2007-09
LY55204301752007-09
LY65604503502007-10
LC9450290x2007-12
LFA450360x2008-09
LH8450290x2008-09
LMG5204301752008-13
LS3418x1102008-17
L98490x2002009-10
LS9531418x2009-13
L9H418x1102009-13
LSA418x1102009-15
LZ1450360x2010-12
L20355260x2010-12
LH9450290x2010-12
L94418x2010-14
LMF5204301752010-14
L99418x1102010-15
L965604702562010-20
L77 (automatic)442.6xx2011-16
L77 (manual)482.2xx2011-16
LT15754651622014–present
L83450290x2014–present
L86450290x2014–present
LT45294201202015–present
LT55754651622018–2020
LT25754651622020–present
L8T610545241.62020–present
LSX376450x230Aftermarket
LSX454R568x230Aftermarket
LSX454568x230OEM

What Is The Weight Difference Between An Aluminum Or Cast-Iron LS Or LT-Based Engine?

Of course, the weight difference between an aluminum or cast-iron LS or LT-based engine differs between the available engines. However, as a general rule of thumb, people within the community expect an 80-pound weight difference between the engine with the cast-iron version, of course, being the heaviest.

Furthermore, there are also many instances in which the engines have both aluminum or cast-iron piston heads. Without a doubt, there’s also a weight difference between these heads, but how much would that be? In general, an aluminum head weighs 25 pounds, whereas a cast-iron head weighs 45 pounds each. Therefore there’s a 20-pound difference for each head.