New guy/New Thread-LS9, LSA, LS3 for project builds
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Joined: May 2026
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New guy/New Thread-LS9, LSA, LS3 for project builds Howdy everyone,
I'm new to the forum here but been doing this awhile & you guys have actual tech convos. I've got an interesting one but may have been answered 1000 times already:
Dave
I'm new to the forum here but been doing this awhile & you guys have actual tech convos. I've got an interesting one but may have been answered 1000 times already:
- I am starting an N/A build from scratch-I get to pick and build the engine, the wife gets to pick the car or truck I put it in. I want to build an LSA (12673476) or LS9 (12623969) but the bare blocks are nonexistent.
- I like these blocks due to the internal strength and the piston squirters, but other than that are they basically just an LS3?
- I'm putting a Callies balanced assembly in it/Diamond pistons good for over 1,000HP... but I'm going to run it N/A around 550-600 with the heads/cam/intake I'm sourcing- can a production LS3 hold that together without much problem? I've seen these things push WAY past what I'm trying to do, but I don't want anything changing shape under load.
Dave
Howdy everyone,
I'm new to the forum here but been doing this awhile & you guys have actual tech convos. I've got an interesting one but may have been answered 1000 times already:
Dave
I'm new to the forum here but been doing this awhile & you guys have actual tech convos. I've got an interesting one but may have been answered 1000 times already:
- I am starting an N/A build from scratch-I get to pick and build the engine, the wife gets to pick the car or truck I put it in. I want to build an LSA (12673476) or LS9 (12623969) but the bare blocks are nonexistent.
- I like these blocks due to the internal strength and the piston squirters, but other than that are they basically just an LS3?
- I'm putting a Callies balanced assembly in it/Diamond pistons good for over 1,000HP... but I'm going to run it N/A around 550-600 with the heads/cam/intake I'm sourcing- can a production LS3 hold that together without much problem? I've seen these things push WAY past what I'm trying to do, but I don't want anything changing shape under load.
Dave
On The Tree
Joined: Oct 2011
Posts: 127
Likes: 44
From: Colorado
The LSA and LS9 blocks are roto-cast out of stronger aluminum than the LS3. They also have cylinder liners about 1/2" longer than the LS3 so are better suited for stroker kits. The LS9 is supposedly finish machined and uses steel main bearing caps; the LSA block is as-cast and uses nodular iron main caps, a bit better than the LS3 cast caps. My build used an LSA block. The deck was pretty flat but 0.002" to 0.003" taller than spec. My CP pistons were machined to be 0.005" out of the hole with 6.125" rods and I used a 0.045" head gasket to get the desirable 0.040" quench. The block was align honed just to be sure the main journals were true and the cylinders honed out to 4.070" to make sure they were round when using ARP head studs; the clamping force of those studs can distort the aluminum block. ARP head and main cap studs are good insurance to keep everything together. A Google search found several places advertising LSA blocks but I didn't call to verify that they were in stock. IMHO, a LSA block w/ oil sqirters is worth it over an LS3 unless money is tight. Don't skimp on conrod bolts! When you spec out your valve train, look into BTR or YellaTerra shaft rocker systems and Manton Series 5 pushrods.
