You are so full of crap. The man said he doesn't even rev over 5K. Modern Hemi engine and LS are very comperable as they are practically identical in specs. HP is HP my friend don't matter if its a blown 302 Ford or a built 632 CID big block. 1-7/8" is a bit overkill even for 364 cubes.

 

I've saw Dyno and track gains going from a 1 3/4 to 1 7/8 on a 6.0

This **** isn't new it's been done plenty of times

Hell awhile ago there were 6.0s with 2" primaries

So if you want to talk full of **** then look no further then the man trying to push try Y setups and 1 5/8

Before you come at me spend time on yellow bullet ls1tech ls1trucks and bunch of other LS sites

We're not referring to some SBCs and modern HEMIs suck compared to a LS

I spend enough time on the Dyno to know what gains and what doesn't on these motors

 

1 5/8" Tri-y will build torque in a stock 4.8 and that is what the man is attempting to find.

I can't help that you are too blinded to understand the effect of having header primaries that are too big. I have seen a 500 hp 406 small block lose 47 ft/lbs of torque at 2,600 rpm going from 1 5/8" headers to 1 7/8". The dyno was done after the car slowed down at the track with the larger primary tubes. I had 14 gauge 1-3/4" primaries on my Titan but I was making alot more power than a stock 4.8 or even a 6.0L for that matter.

 

Hp and torque below 5k is the name of the game for me i never rev higher than that to keep my trans happy. Even torque more so than hp because the 4.8 is small and the truck is heavy need to make all the torque improvements possible

 

you are comparing busted *** SBC to LS motors they arent the same, please quit posting about SBC stuff and look into this matter...you will find youre all alone in this game trying to push that garbage

 

Actually I am not alone. Looked up several people running the Thorleys on 4.8s and 5.3s and not a one of them said they did not feel a torque increase. It doesn't matter what engine you are running HP is HP and a ~300-400 hp engine will make the best torque curve with 1 1/2 to 1 5/8" primaries, maye 1 3/4 if it is turning 6,000+ rpm. Physics do not suddenly change because the "Almighty dyno queen" LS engine is attached to the header tube.

 

can definitely tell youre not up to par with now talking of 1.5 primaries, with said im done with this


to the OP dont restrict the truck for future plans, youll only be spending money more then once if you do

 

More than up to par when it comes to engines. If those large primaries work so well, better than a more reasonable primary size where are you time slips and dynos? I have used 1.5" primary shorties on an engine making close to 400 hp and it pulled strong from off-idle to 6,000 rpm. 1 5/8" would have been better but were 3x the cost.

 

This was a comparison between oversized Pacesetter headers and a set of 14-gauge 1-3/4" equal length merge collector headers. Its no comparison to which one would be quicker. The oversize primaries generally lose everywhere under the curve for little to no gain up top.

 

im with George c nothing smaller than 1 3/4 or youll be kicking yourself in the nuts later,i know cause I went 1 3/4 then 1 7/8 and better all across the board hp and tq