not sure what to use on my 383 do you get more power with longer rods? i would think the longer rods would be heavyer and wouldnt rev as well?

I heard that when building a 383, if you use 6" rods it puts the wrist pin pretty close or in the bottom ring grove. I have also heard that the difference between the two rods is so minimal, that you're better off going with a 5.7" rod and not having the wrist pin so high up on the piston.

Makes sense to me, I went with 5.7" rods.

I could understand if you want to get a crank that will balance internally, I believe they all need 6" rods. Then your engine would appear as a regular internal balance 350 from the outside. If that matters to you at all.

I'm interested to see if anyone else has anything to say about it also...

I used the 6" because the rod/crank ratio is closer to stock than the 5.7s.

5.7"/3.48" = 1.6379 stock 350
6.0"/3.75" = 1.6000 stroked 383
5.7"/3.75" = 1.5200 " "

you can internally balance with either rod but its easier and cost less to balance internally with 6" rods because it generaly wont require heavy metal balancing. There is negilble difference powerwise between the 2.

If I wanted to boost or run nitrous what would be better?

I would use what costs the least. Like was said above powerwise there won't be any difference.

You do have a third option, several rod companies have 5.85" rods which work with 383s or 395s. I used this rod in my 395 because I did not want the wrist pin so high up in the piston (in the ring grooves). Trick Flow and Eagle have these rods.

BTW: it is not the rod length that anything to do with power. You should be talking about crank throw instead, AKA, long stroke VS short stroke.