I have found many posts on this and still don’t think I have a solid answer. Can I take an L33 5.3 bore it out and use stock ls1 pistons in it. In essence make an ls1 out of an l33

 

Yes there are machinists that will do this it has been done many times, a better question is do you actually have one of these engines, and can you find a machinist who's willing to do it for you?

 

Yes. That's what in the race car.

 

If you paying to bore the engine get it bored to 4.0 and use LS2 or 6.0 pistons.

 

I don’t think you can go all the way out to a 6 L I guess of my concern it will the cylinders be too thin at a stock LS bore. If they use the same basic sleeves in an LS1 in the aluminum 5.3’s then I would be fine I have an extra set of LS one pistons rods and I found a rebuildae l33 code for sale for $300.