LS1 cast iron or Alum.

[beertestr]

For all intents and purposes, it's damn near 100#, like 97-99#. I weighed my bare 5.3L, and my bare LS2 block, and a junk LS1 block, came pretty close to that.


As for overbore, the LS2 and LS3 blocks OEM recommended overbore is 0.020", and you can get service pistons if needed. LS1 Blocks are recommended for a max of 0.010 overbore. The 4.8/5.3 Iron block allows the biggest over bore, I know you can at least go to to the 3.898" (aka 99mm) LS1 bore, not sure if you can 0.020 or 0.010 over that like on the aluminum blocks.

Not sure if this worth mentioning, but there is a very small number of the 5.3L aluminum blocks that are actually LS6 block CASTINGS, with the smaller 96mm cylinder liner. These can be overbored to 5.7L. Again, these are very rare, but they are out there in the LM4 equipped 2004 Rainiers, 2003-2004 Trailblazer EXT, 2003-2004 Envoy XL/XUV's, and 2003-2004 SSR's.

As for the other iron blocks, I have seen people going 0.060" over, not sure what is the max-safest overbore. OEM calls out 0.020, but what the aftermarket has been doing seems to be going a little further than that.

Just reading over the engine builder article revealed lots of incorrect info, but in general it's more correct than it's wrong.

[r.barn]

For all intents and purposes, it's damn near 100#, like 97-99#. I weighed my bare 5.3L, and my bare LS2 block, and a junk LS1 block, came pretty close to that.

lol

now have

65 lbs
99 lbs
170 lbs


Personally 100 lbs "sounds" about right. Thought 65 sounded low, but
thought 170 was high too.

For as cheap as you can get iron truck blocks for I just dont see paying
extra for the aluminum. Maybe in a drag car where you're counting 10th's
but dont see the difference in a 5,000 lbs truck.

[ma.racing]

lol

now have

65 lbs
99 lbs
170 lbs


Personally 100 lbs "sounds" about right. Thought 65 sounded low, but
thought 170 was high too.

For as cheap as you can get iron truck blocks for I just dont see paying
extra for the aluminum. Maybe in a drag car where you're counting 10th's
but dont see the difference in a 5,000 lbs truck.

what he sead if you had a race car it would be one thing but you have a 4x4 truck

[beertestr]

Can I vote twice? 100 is the closest answer... there, I'm stuffing the ballot boxes.
Maybe I should take some pics of me weighing them next time I have a bare iron block to weigh, the 2 I have right now still have cranks, cams and covers on them.