The Buick V6 pistons need GMC "419" rods with some modification to the small end for the smaller Buick pin, and narrowing on the big end to fit the Chevy crank. There are a lot of different compression heights and styles of Buick pistons, I am not sure which ones to use but they need machining for valve to piston or head to piston clearance. There is a better selection of off the shelf rings for Buick pistons. Standard Buick bore is 3.800".
Stroking with 292 rods has been done, but I think with custom pistons. There was an article in "The 12 Port News" from Inliners a while ago.
I looked into using Toyota Landcruiser 2F rods. They have the same width big end as GMC and a smaller journal diameter but are a lot longer (7.7") and wont work in a Chevy. They might work in a GMC with custom pistons.
I have heard of blocks bored out to accept wet liners. I am sure you will find some way of doing it.
