im trying to put together a fi build and was goana do a ls2 block with stock crank, forged rods and pistons....but now ive seen a few ls3 blocks foating around and heard they are actually stronger then ls2 blocks? is this true?

also im assuming they use the standard ls1 6.125 rod, and stock 3.622 stroke with the only differance being a 4.030 bore? if so it seems to be a good alternative to a 370 ci? if i use one of these i dont have to bore it and take meat from the sleeves, i can leave the sleeve alone and gain a few cubic inches

just to double check gm didnt take the ls2 block bore .030 over and stamped with a 6.2l on it is it? do they actaully have a differant sleeve in them that is comparibly think to the ls2 block? im worried about streingth most, and making sure it doesnt require a differant/special stoke/bore/rod

 

ttttttttt

 

a ls3 block has a 4.06 bore and is 378ci

 

It is 20% stronger then the LS2 block also. That is the best reason to use it. They made some areas around the mains stronger. A Corvette mag had a story about all the changes.

 

any link to that? seems like a good canidate....

and the bore is a 4.06? i thought it was 4.030?

 

I thought ls1 rods were 6.098, aftermarkets are 6.100 or 6.125

 

You are correct, sir!

 

Are the L92 and LS3 blocks identical?

 

yes supposedly they are. Only thing that changes are that LS3's which are in vettes, have a much different cam profile, along with minor small details that all add up very quickly to make those 435 horsepower compared to the 407 hp of the truck engines. Those details in the Vettes LS3 include lighter "hollow" valves, completely different and higher flowing exhaust, the cam like i said already, intake manifold, throttle body, air intake, Just a bunch of stuff. It all adds up

 

Same blocks, cranks & the bare heads all other things are different. The web area around mains are better & stronger with a new design making the L92/LS3 20% stronger.

 

Also, LS3 blocks do not have the provisions for the DOD, makes it a more straight forward install than the L-92

 

I did a search a while back on these blocks were supposed to have some issues, like the bores being off center.(Cant find the pic's)

https://ls1tech.com/forums/showthrea...92#post6093221

https://ls1tech.com/forums/showthrea...92#post7990851

https://ls1tech.com/forums/showthrea...106&highlight=


Have they resolved these issues yet?