Gains From Changing Mid Tube To Long Tube?

I am working on a LE2 383 motor. here is the details:


Eagle Cast Steel Crank 3.75" Stroke
Eagle Forged I Beam Connecting Rods
ARP 12PT CapScrews
SpeedPro Forged Hyper Coated -12CC Dished Pistons
.026" Head Gasket
.010" Deck (Pistons .010" In The Hole)
11.7ish SCR / 9.1ish DCR
LE2 Ported Heads W/Comp BeeHive Springs
7/16" Studs - GM Guideplates
Comp Pro Magnum 1.6RR NSA W/Polylocks
Clevete Main, Rod, and Cam Bearing
LE2 383 Billet Cam 23X/23X @.050"
.600 Total Lift
ProProducts Twin 58MM TB
Aluminum Elbow
SLP Cold Air Induction
Pacesetter MidTube Headers
SLP LoudMouth Catback & Flowmaster Catback (I have both, unsure what I will use)
EGR Delete
Cat Delete
Air Delete
TunerCat (Pc In Car)


So. I notice that just about everyone uses long tube headers. I would imagine there is a HP gain to be had. My car came with MidTube pacesetters when I bought it. I have no idea on the exact hp this moror will make but I think it should be a bit over 400RWHP (I HOPE!). My question is would it be a good idea to dump these midtubes and get some longtubes?.. what kind of gains are there to be had?..

My car does not need to pass emissions so I am not worried about that at all.

Thanks for any advise!


found a post that said "according to Horsepower TV they dynoed a SBC with LTs and then with mids...hp numbers were identical but they lost a little low end torque with the mids."

Peak horsepower would be pretty close to the same but the LTs would make more power everywhere below peak hp. The power difference would be the greatest at lower rpms and the power difference between the two would get smaller and smaller as you got closer to peak hp.

If you do choose to do the swap from mids to long you should do a dyno pull with both setups that way we can all see the results. I know that there is a bunch of us on here that would like to what gains might be had with the switch.

Well. I will definatly keep my mid tubes for now. and I will be dynoing it in a few weeks when I get it broke in and somewhat tuned.

Thanks for the info. I will have to see how the car feels, but for the price of the upgrade compared to the gain I will just use my midtubes for now.

LT's and True Duals will make that thing sound so nice. Id do it, and than theres the 15 extra hp. Those headers are not mids. They are shorties, the only mids that exist are slp's with a 1 3/4 primary and As&m's 1 3/4 primary. Everyother company is a 1 5/8.

yea your right. mine are only 1 5/8 primarys. that sucks.. I will be puttin LTs on but not right away. I will get some dyno numbers before and after. I need to be sure my engine runs and works good before I put alot more money into it. this is my first project. I dont know if I want to tackle the true duals. but we will see,.

the td's will sound like sex, about as good as it gets

LTs will make more power and torque across the board than mids, hands down. If you don't care about ground clearance (certain LTs tuck up very nice though) and spending some more bucks, get the longtubes. You won't regret it.

Ive had both LT's and mids in my hands...just by looking at them its very very clear the LT's make more power all over the curve.

I recently sold my RK sport mid tubes and installed LPP (mini catted) SS long tubes. With the mids my motor did not make big power and pin you back till 3.5K RPM.

The LT's build big power and pin you just under 3K RPM. Up top feels about the same. Big, huge difference at lower to mid RPM's.

Wish I did the LT's long ago.