i have a 04 silverado with a 4.8 resent 4l80e swap not much going on with it currently efans, CAI and TM removed adding a wideband to play with the tune and a 2200/2400 converter to swap out the diesel low stall thats in it now, future plans are 6.2 boosted (have the 6.2 sitting) but its a while till that gets installed so in the mean time since i cant leave things be i picked up a passenger side exhaust manifold and the dual exhaust section from the manifold to the muffler off a 6.0 while out getting parts for my 80e swap pretty cheap so i couldnt say no

so my question is are the pipes to big for the 4.8 will i be hurting power? i think there like 3" my plans are 6.0 mid section (no cats) x pipe to 2.5 magnaflow mufflers and maybe some resonators if its to loud have it exit in front of passenger side tire or dump before axle

 

IMHO I think 3" would hurt you.

 

I agree with the no cats, but I also believe the 3inch on a 4.8 would hurt its power

 

Yeah I know 3” is to big but stepping down to 2.5” x pipe and mufflers so not sure?

 

i got around to measuring the pipes today pretty surprising!

the inlets where they connect to the manifolds are 2.35" I.D. for about 10 inches then they get bigger O.D measured right at 2.98" so im guessing 2.75 I.D? then the bends measured 2.50 O.D

im probably just going to install them and try see how it go's? i'll do some logging before then after. at this point its probably $40 in supplies and i get to use my chop saw & welderMurica! LoL!

 

I run 2 1/2" duals off my LT headers with an X pipe
from my 6.2, rear cats only. no prob with size. It's a DD.

 

i'm going to be installing some kooks headers a friend gave me to to square up some work i done on his truck, was installed on a 09 escalade there 1.75 primaries 3" collectors with 3" y pipe with cats i might cut the y pipe make dual pipe reduced to 2.50" or just run no cats 2.50" dual pipe right from the headers not sure at this point