Shorty Headers

[PlayingWithTBI]

There is definitely a very noticeable gain with shorties. Stock manifolds are horrible and then again so is the whole 1500 exhaust system.

^^^Yes - once you add a mandrel bent Y, a 3" high flow Cat, and high flow (especially a straight through) muffler, you'll see quite a bit of performance increase.

 

[L31MaxExpress]

^^^Yes - once you add a mandrel bent Y, a 3" high flow Cat, and high flow (especially a straight through) muffler, you'll see quite a bit of performance increase.

That or running them on the larger GM exhaust. My Express was dual 3" to the muffler from GM, pipes bumped up right off the manifolds. The 8-lug GMT400s are 2.75" dual to the muffler.

 

[SuperSpore]

There is definitely a very noticeable gain with shorties. Stock manifolds are horrible and then again so is the whole 1500 exhaust system. The best part is the shorties typically do not crack in half like the iron manifolds do.

This right here... for me it's worth it to avoid dealing with cracked manifolds, or worse... broken bolts in the head. Sometimes they shear off on their own, without the help of someone trying to remove them. Even if there was zero hp/torque benefit id still swap to shorties to avoid the headaches.
That's just me though, some people may love the aesthetics of cast iron.