Darton sleeve correct part number.

This is what was used in my aluminum 5.3 block which is now virtually identical to an LSA, minus piston squirters. If I remember right it was 12 weeks from Darton. Nobody has shelf stock. LA sleeve is another option.

If you are only replacing a single sleeve I’m not sure if you’ll want -DF (dual flange) or no flange. Dual flange is for when you’re between two other darton sleeves. These are 4.000” bore so your machine shop has to open them up to 4.070”.

If you're doing the whole block, you'll need the quantities and part numbers I have above. DF on the center two cylinders, SF on the outside. Really you could use 8 of the DF and you'd have a small open space on the outside sleeves. It was about $1250 shipped for everything in early 2021

This was the email contact I had.
[email protected]