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Discussion Starter · #1 ·
Trying to decide on a LS9 block or an LSX. Will be using these as I can get them for cost at my dealership. (shipping to Canada is very high). Noticed the LS9 uses the same main caps as the lsx. Noticed it was also rated by GM for 900hp and the LS3 was rated at 550hp. So is it really that much stronger then the LS3? The 12mm headbolts wood be a plus as I only have 4 bolt heads. Never really hear of anyone using these, is there a reason for that?
 

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Doesn't the LS9 block use 1/2" studs?

People have made a lot of power with that block. That being said, it seems to me that the iron block would most certainly be stronger.
 

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I ran an LS9 block with stock LS1 crank, Compstar rods, Wiseco pistons, and MAST LS3 heads, stock LS3 intake, 90mm cable TB with an 88mm turbo making around 1400hp for years and no issues. Over 200 passes in the 1/4, 1/2 mile, and lots of street pulls. I would say easily 100 1/2 mile passes. It never lost a head gasket or any signs of coolant consumption. Granted it only had a few thousand miles on it and was pretty much only raced when driven. e85 fuel and Holley Dominator EFI

I ultimately snapped the stock crank doing a 1-4 burnout and my speedo showed 140-150mph when it finally hooked up.... and shut down the engine. I coasted to the end of the 1/2 mile runway and then into the pits..... quickly started it back up to hear a clanking noise... the rear rod journal on the crank was snapped cleanly all the way thru. The only thing holding the crank togther was the clutch/trans and 2 rods. After tear down it just needed 2 rods and a new crank for the big hard parts. Block was fine thankfully!

http://ls1tech.com/forums/attachmen...pped-crank-turbo-ls9-rx7-broken-ls1-crank.jpg

This time put in a forged crank for good measure..... never intended to make that much power when first put the shortblock together.

Engine runs LS9 gaskets and ARP head bolts (not studs). Makes 1060rwhp/1070rwtq on 14psi boost. We run it at 19-22psi in 4th and 5 gear which I can only guess is around 1400hp as this turbo is rated at 1400-1450hp. From 10-14psi it was gaining around 50rwhp per pound of boost on the dyno. We never went higher than 14psi on the dyno sadly.

The LS9 block is made from a better grade aluminum and is also rotocast (less porosity). Additionally it has billet main caps plus piston oil squirters.... which certainly doesn't hurt to prevent hot spots on the piston crowns ;).
 

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I'd say weight (load) has a lot to do with its survival. JMHO.
 

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I ran an LS9 block with stock LS1 crank, Compstar rods, Wiseco pistons, and MAST LS3 heads, stock LS3 intake, 90mm cable TB with an 88mm turbo making around 1400hp for years and no issues. Over 200 passes in the 1/4, 1/2 mile, and lots of street pulls. I would say easily 100 1/2 mile passes. It never lost a head gasket or any signs of coolant consumption. Granted it only had a few thousand miles on it and was pretty much only raced when driven. e85 fuel and Holley Dominator EFI

I ultimately snapped the stock crank doing a 1-4 burnout and my speedo showed 140-150mph when it finally hooked up.... and shut down the engine. I coasted to the end of the 1/2 mile runway and then into the pits..... quickly started it back up to hear a clanking noise... the rear rod journal on the crank was snapped cleanly all the way thru. The only thing holding the crank togther was the clutch/trans and 2 rods. After tear down it just needed 2 rods and a new crank for the big hard parts. Block was fine thankfully!

http://ls1tech.com/forums/attachmen...pped-crank-turbo-ls9-rx7-broken-ls1-crank.jpg

This time put in a forged crank for good measure..... never intended to make that much power when first put the shortblock together.

Engine runs LS9 gaskets and ARP head bolts (not studs). Makes 1060rwhp/1070rwtq on 14psi boost. We run it at 19-22psi in 4th and 5 gear which I can only guess is around 1400hp as this turbo is rated at 1400-1450hp. From 10-14psi it was gaining around 50rwhp per pound of boost on the dyno. We never went higher than 14psi on the dyno sadly.

The LS9 block is made from a better grade aluminum and is also rotocast (less porosity). Additionally it has billet main caps plus piston oil squirters.... which certainly doesn't hurt to prevent hot spots on the piston crowns ;).
Thank you for sharing
 

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Discussion Starter · #9 ·
Thanks for the info! An ERL block would be nice, but I don't have a core. By the time I figure that, shipping and duty its just way to much for me. Its the heavy LSX block for me or the LS9. Thanks for your info gnx7! I am leaning more to the LS9. Not sure yet.
 

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I researched this a few months ago. The 2012 and newer LS3, LSA, & LS9 all share the same casting (12621766). The LSA gets machined for piston squirters and has cast steel main caps. The LS9 gets machined for squirters, 12mm head bolts, and gets billet main caps. Also, the LS9 gets a better material liner than the others, I believe.

I had my hands on a few LS3 and LSA blocks, and the core shift was terrible! I decided to go with an LS2 block instead because of the thicker liners with no core shift.
 

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Thanks for the info! An ERL block would be nice, but I don't have a core. By the time I figure that, shipping and duty its just way to much for me. Its the heavy LSX block for me or the LS9. Thanks for your info gnx7! I am leaning more to the LS9. Not sure yet.
When I asked ERL in another thread, they pretty much said the 5.3 blocks are the strongest to start with as a base for their process anyway. And the cheapest which is handy.
Not much to figure out with a core, just pay the surcharge and they start with a brand new one, think their site states around $850 for a 5.3 alloy block.

Although I would have no hesitation in using an LS9 block. The fact it already has billet/dowelled caps and oil squirters is a huge bonus, as those would easily be at least another $1000 on a normal block.
And bigger studs too...although no doubt ARP will ask a premium for their versions.
 

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I have access to (2) LSA longblocks and 1 LS9 longblock that are GM warranty motors.... meaning they need rebuilt and have no blowers. Just heads/shortblock/front/rear covers.... sometimes oil pan. They don't have huge issues with them. ie not holes in the block ;) but do need to be fully torn down, inspected, most likely overbore/new pistons/rings/bearings. They are located in SoCal. Will not separate the blocks.

Any interest email me: [email protected]

new LS9 block is $3350
12621983 LS9 6.2L Bare Block
*they typically are ready to install parts whereas an LSx or other aftermarket block needs lots of checking/machining to get it ready.
 
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