can someone explain the difference in the flanges for a turbo will the t6 flange make more power or what???

 

AFAIK the T6 is larger so it will support more airflow(power) before back-pressure becomes an issue, but spool can be later, all things being equal.

 

Yup T6 is considered a large frame turbo, T4 is a medium frame.

Spool depends on a lot of variables combined with rear housing size and A/R. T6 has higher flow potential.

 

I would be looking at using a T6 frame with anything that was single turbo and over 4.5L

T4 is excellent for 2.6L-4.5L

T3 is great from 1.5-2.6L

And a T25 covers everything below 1.5L

People usually can go outside of those displacements based on how high they are revving if they need more flow, or maybe they aren't revving and moving much air at all so they can go smaller.

Those are just generalities.

 

Seems like the T4 is pretty popular for the LS stuff under 1000whp.

 

Depends on which turbos you are looking at and the power you want to make. T4 is a up- charge on most Borg units, so if you can package the T6 it will save you a little.

 

Im on the fence right now. I have a 416 that I am adding a single turbo (BW billet 485) and I keep hearing to go T6, but I dont foresee me going over 900 rwhp. But we also know how things go after a while... LOL.

 

I would really urge you to go straight to the t6. I didn't, and will be replacing the t4 to go to a t6 soon.
Especially with your cubes

 

So fitment/space shouldnt be an issue? Seems I see plenty of people with singles or even twins on first gens.

 

Go T6 bro. Been there, done that. Only reason I swapped to T4 was because I got a great deal on the billet 75/83 BW. The boxed 7596 S475 spooled surprisingly quick for a low compression 4.8, you'll be happy with a T6 and billet S480 or 484 on a large turbine on 416 cubes.

 

Wish I never touched T4 stuff personally. T6 all the way with single setups.

 

Not to bring this up from the dead, but how about t4 vs t6 at high elevation? Living in Albuquerque at 5300' average track da is 7000'-7500'. Building a 370 this winter and trying to get turbo size narrowed down on the at and flange side. Will be running a s480.