im going to add from my old post that is 2 years old , what is this ?? In the picture ? i know it goes from the intake manifold to the fuel , but what it is ? its from my Stock ls1 , but what can i use for my 402cid engine ? can i use this same one ? first i would like to know what its all about ..

Im GM PART # on this is 12570469 but it said that this is the new part #12597341 Can i switch this over to my 402cid engine ?

 

Its a fuel vapour canister. Bit like a PCV valve for your fuel tank - but pressure regulated.

 

If i were to have an ls2 with a drive by wire throttle body, and wanted to go with a throttle cable driven 4 barrel TB, would that be an easy conversion, or will i have problems with computer, and tuning?