Tell me what you all think. Drawbacks or is it even possible. I dont wanna hear how building a 305 is dumb though lol.

um, I thought that a 3.8L is a buick V-6, and a 305 is a V-8. I mean, this seems so simple that maybe i'm thinking of a different 3.8? or that is just a dumb question.
I'm going to say not possible.

Sorry I shoul'd of explained. A 3.8 inch stroke crank. Like how the 383 is 3.75. Few companies make a 3.8 inch.

Possible - yes.

Drawbacks - trying to make a silk purse out of a pig's ear.

3.75" stroker (400CID cranks) are common, put in a 305 is kinda rare, but a few have done it, 3.8" is only .050" more, can't see that as being too much of a problem. You'd have to do the standard clearancing things, grinding, rod bolts, etc, just a bit more I imagine.

but of course....why?

But if it's a really, really good sow....

Seriously, spending the time, effort, and cash on balancing a set of smaller pistons and rods to such a crank probably won't generate as much effect as doing the same thing with 4" pistons, or 4-1/8" pistons.

Don't forget custom pistons (pin height).

That's the real question.