Can anyone tell me if I should center cv cross member I.e. aligned with spindle of the old solid axle or should I move it forward to center wheel in fender well ? And how far forward of axle / spindle center line ?

 

It seems like everyone is moving them forward an inch or so to get them lined up in the fenders and to clear the firewalls.

 

I moved my CV ifs forward one inch to center the wheels in the fender openings. It was a personal decision which is not required but it allows the tires a bit more clearance for turning.
My front end is about 5 and 1/2 inch lower with the new ifs so the tires are much closer to the fender opening than they were.
My 55 build thread shows my IFS installation.

 

Goeasy, what year truck are you working on? It makes a difference as you don't want to move it forward if it is a 48-52.