I'm still just learning all this stuff and was wondering if i got a 383 or a 396 would regular lt1 headers still fit.

 

as long as your talking about keeping the lt1 and stroking it to that CI

 

Yes, LT1 headers will work from a standard 350 would work on a 383 or 396 LT1 as well.

 

Altering displacement (bore+stroke) should not change the overall size of the engine or the exhaust bolt pattern. I don't see any reason why it would not fit. Now, if you are buying a non-LT1 crate engine that is another story.

 

well, i looked into it, and i think when the time comes either rebuild it and change it to a 383, or if it will work and can find a way to get it done cheaper, swap it with a new ls1 and get the 400hp SLP package to replace all the mods ill lose from swapping

 

In that case, you'd have LS1 heads and need LS1-compatible headers.
I'm not sure what kind of clearance issues you may have fitting them into an LT1 car. (I'm sure someone here knows the answer)