which size headers for ls1 1.5 1 5/8ths
 

Sanderson gave me another pair of headers to try as I wanted to see if the 1 5/8ths would fit. They seem to fit as well as the 1 1/2. I thought that it might be tight on the steering shaft, but its not too bad. They said that they can dimple it for me before i get them coated. So with that being said I have a stock ls1 with an auto. I just want to get it running, maybe some day in a few years I will put in some bolt ons s/c or something of that nature but for now mostly stock. should i go 1 1/2in primaries or 1 5/8th in ?

This will be going into my 49 5 window.

Thank you