Just like it's big brother, the SBC based 90 degree V6's all interchange. It'll be like putting heads off a 350 on to a 305 (350 & 262 share the same bore as do the 305 & 229). In my opinion a 229 with a turbo will die a glorious death. With the money & effort, I'd work with a Vortec version of the 262 to do a turbo V6. Another thing, outside of what directly can be interchanged between the SBC & V6 there's really not much out there for Chevy V6.
Funny, I have a few minute conversation with a guy today at the swap meet that touched on just that issue.
I brought a spare performer intake for the buick v6 and tossed it on the table just to see what would happen.
Turns out, this guy was involved with racing vehicles that have a 4.3 because it's what was around at the time. We got to discussing how seemingly little of the performance stuff from the GM v6s of the day show up in circulation, obviously excluding the buick turbo versions.
Back to the OPs thread though, I'd say just enjoy it as is if it runs good. The expense you incur doing a turbo setup and head swap would be better going to a sbc V8 in this case, in no small part due to the fact that it's not even an original motor already - so there's no numbers matching argument which, for a v6, borders on silly itself outside LC2 areas.