with a D16Z6, some dude is telling me a t3/4 with .48.60 would start spooling at earliest 5k rpm!! it tha`t true or not?

 

No direct exp. w/ that turbo, but even on a SOHC the .48 turbine should start building positive manifold pressure (2nd gear roll on) at least by 3500 and reach around 7-10psi by 4000-4500.
5000 is bit high. Of course maybe he has mad 'spoolin' skillz....

 

Manifold design, wastegate design, cam's, compresson, head work, downpipe all come into factors for spool times dude.

Jeff