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I have researched several resources to determine just how much lighter an all-aluminum LS engine is, compared to the Gen I iron block / iron head engine, and many of those sources were based on hearsay and speculation. I recently had the oportunity to do an apples-for-apples (with some minor exception listed below) comparison with some precision test equipment and thought I would share my findings here.

The test subjects were as follows:

The Gen I engine is a 1994 350 equipped with TBI. This engine was just pulled from my 1967 C10 and was essentially just as it ran in the 1994 K-1500 that it came from. It was complete with all injection components, all accesories including AC compressor, ps pump, alt, and cast iron water pump, mechanical fan and all pulleys The flexplate, starter, exhaust manifolds, engine mount brackets, wiring harness, spark plugs, etc., are there as well. It was literally weighed as it was being pulled from the truck - still hot, full of oil and oil filter still on it.

The LS sample is a 5.7 all-aluminum LS1 from a 2000 F-Body. It too is fully equipped with all accesories, including AC compressor, alt, ps pump, pulleys, spark plugs, (wiring harness was draped over it just to include it in the test). It has LS1 intake and factory Camaro exhaust manifolds as well. Also bolted to the side are adaptor plates for the engine brackets, but no brackets.

Here are a few of the differences that may skew the results a couple of pounds in one direction or another. I figure these should make less than 10 pounds difference, but you be the judge. (Before I install the LS1, I may try to correct some of these differences and I will post an update).

The 350 still had whatever coolant was remaining in the block.

The 350 still had fuel lines attached - the LS1 did not (fuel rails/injectors were there though)

The LS1 did not have the MAF or any intake piping and the 350 was not weighed with the breather attached.

The LS1 did not have plug wires.

The LS1 PCM is a bit heavier than the TBI's.

Note that the LS1 will use an electric fan, which, though not a part of the engine, should be considered as well.

LS1 did not have accesory belts installed.

The equipment I used was a suspension scale rated for 2000 pounds and is certified accurate within 5 pounds at full scale. This scale is strictly calibrated and controlled by my employer and is checked before and after each issue. It was on loan to me for this purpose.

Results:

350 TBI = 620 pounds
5.7L LS1 = 450 pounds

So we could safely assume a difference of about 150 pounds had the configurations been perfectly matched.





TBI still hot and on the hook.




TBI weight...620 (too many carbs i guess)




All accessories accounted for.




Ahhhh... much better... a smidge under 450.




Gravity not as effective this time...

Smokin00WS6

iTrader: (4)

Pretty cool info...thanks for sharing