Would true dual 3'' be too much on a non-FI 4.8? Am I going to find a loss on the low end?

I plan on going FI at some point, and in the meantime I want to plan my exhaust accordingly....

 

It is if you dont have the set up to support it..

to run a true dual 3inch..
you would need gears and a higher stalled Torque converter to make up for the loss of bottem end..
a stock motor probably wont like the bigger exhaust but if you have a cam and other bolt ons you "could" see an improvement
You will flow much better at the top end,
but you can only flow as much air as you can stuff into the engine
I changed out from a 2-1/2 true dual setup, to a 3 inch true dual set up and gained .6 tenths of a second at the 1/4 mile..

 

Well if you are planning on FI, go ahead. If it were me, I would just get the exhaust, then put it on when you get your choice of FI.

 

Its too big unless you plan on building the truck to actually use that big of an exhaust setup.

 

what thunder said, lose on bottom-gain on top. 2.5 would put you in the middle.

 

I had 2.5" duals on my RCSB 5.3 i had and i still lost a little bottom end.

I would do 2.5" duals. That gives you a little room to grow but it wont be overkill like the 3" duals would be.

 

unlless he has the mods to support it..
I dont know his modifications on his truck...
need to start over, and find out what modifications you have done..
this will determin if you will bennifit from it now..

 

Custom tune
SI/DO Magnaflow exhaust
Doug Thorley "Tri- Y" Headers
Silverado SS Gauge Cluster
Yukon 3.90 gears
Detroit TrueTrac LSD

Stuff collecting dust in the garage:

Corvette servo
Billet Servo
Transgo Shift Kit

its also on my cardomain.com site <--shameless plug.

 

Dual 3" with those mods plus a little boost would be a little much for your 4.8.
If you plan on some serious hp mods with the FI then 3" may suit your needs, but at this point in you build you would benefit most from a single 3" exhaust via headers to a ORY pipe.

 

I agree. your mod list wont support going to dual 3inch...