LMC Exhaust System

[4tiresngas]

Okay, I bought the LMC dual exhaust system. The pipes are not labelled, so I don't know which is left and which is right. I think Solver put one of these on. I know i can figure it out by trial and error, but if someone knows, I'd appreciate some help.

Both pipes appear to be 61 inches long, but one is shorter going up to the manifold. I'm thinking this is the Left side that has a heat riser attched to the exhaust manifold.

Also, anyone know how much of the pipe you are supposed to cut off to fit the system on a SWB. The instructions just say you have to cut the pipe.


Uuuughh

[Jim_PA]

What's the difference in length between a LWB and SWB truck? 20"??? That's how much I'd cut off.

Edit: I think a SWB is 20" shorter...

[red71cheyenne]

B4 you cut anything, lay it all out under the truck and see where its going to go. You can usually tell then, where you'll be needing some doctoring. And like everything else, measure twice, cut once. Good luck, Jeff.

[skillet]

Roughly how many miles per gallon do you think dual exhaust can add over the stock single pipe system?

[farside847]

My MPG did not change much when I switched from single to dual on my 307. MAYBE +1mpg. But I can feel about 15+ hp!!!

[Solver]

If you want I can email what pics I have of mine . About 8 pics very high res.
I couldn't believe they couldn't label them either. tried 2 or 3 times before I got it to fit right. My truck already had the pipes coming off the exhaust manifolds and going back so I used those. So I can't tell you how much to cut off.
Let me know and email me at
solver@evertek.net and I will reply with pics

[BigSky71]

Originally Posted by farside847

My MPG did not change much when I switched from single to dual on my 307. MAYBE +1mpg. But I can feel about 15+ hp!!!

When bought my truck about 15 years ago I had the stock single pipe exhaust system replaced with a complete dual system of 2.25" pipe. I was running the stock ramhorns at the time. I felt a real positive increase in power and as I remember my mileage went up about 2 mpg. Then a few years ago I had the engine rebuilt, used the basic Edelbrock kit, supposed to be about 275hp. I also installed a set of Hedman headers and new 2.5" pipe dual exhaust system. With this combination the truck lost some bottom end, and the mileage went down to about 10 from 13-14. [TH350, 3.55s, 30" tire]. The engine runs real nice though from 3000-5000rpms...

Now with the restoration underway I am considering buying ramhorns [old ones both cracked], besides the long tube Hedmans won't work with the new suspension setup.

[farside847]

Originally Posted by BigSky71

installed a set of Hedman headers and new 2.5" pipe dual exhaust system. With this combination the truck lost some bottom end, and the mileage went down to about 10 from 13-14.

Wow, so you got better mileage out of ramhorns? Maybe I should keep mine in then...

[Longhorn Man]

SWB is 115 inch wheelbase, the LWB is 127... You'll need to cut off 12 inches. I have been wanting to buy the same set up for my rig too, but have not gotten around to it yet.
As for MPG increase, it will be minimal. The bigger the engine and or the more restrictive your current exhaust, the more increase you'll see, but don't expect it to be anything to write home about.

[Ole Blue 68]

I was looking at this exhaust myself; seemed like a good price. How do you guys who have it like it?

[mrein3]

Originally Posted by Ole Blue 68

I was looking at this exhaust myself; seemed like a good price. How do you guys who have it like it?

I bought their kit for my V8 4x4. Nothing could have been easier to install.

Because my truck was originally a single exhaust truck, I had to buy one hanger for the passenger side. Absolutely everything else you need is in the box.

For all you folks worried about buying foreign stuff the kits are made here in MN, out by da-burb's house.

[71-longbed]

same here .. i've been eyeballing that kit for some time now .... its part of my large "to do" list

[LUV2XCLR8]

I looked at them, but I went with custom because I wanted 2.5 inch pipes
over the 2.25 lmc offer, also keep in mind for optimum performance 2.25 is
only rated up to 250 Horsepower, here is the chart that most muffler shops
go by when trying to determine what size pipes should be ran on your rig

*I'm not saying anything negative about them, just saying be sure to do all
the research you need first before making a choice on what you purchase.

[special-K]

More HP means lighter foot/better mileage...Heavy foot/more fun.

[4tiresngas]

Okay, I put it on yesterday. It was pretty easy. I took the old rusty headers and glasspacks and trashed them.

The two pipes coming from the manifolds have different angles with different lengths up. I called Heartthrob Exhaust who makes it for LMC. They also sell them direct and through JC Whitney. They recommended i buy from LMC because they make so many for LMC. LMC is able to give a better price.

Anyway, they said the one with the long up pipe was the driver's side. So, I put the heat riser on the passenger side and the two pipes evened out.

As far as cutting the convert for a SWB truck...I only cut 7.5 inches off. There is enough wiggle room when the pipes go together, that you don't need to cut the 12 inch difference.

Again, I have not been impressed with somethings from LMC. But, this seemed like a good deal. You do have to have ramhorns that turn back on both sides for the kit to work. I got mine at a local salvage yard for $50.

I'll try to get some pictures later.

[mrein3]

Originally Posted by 4tiresngas

Again, I have not been impressed with somethings from LMC. But, this seemed like a good deal. You do have to have ramhorns that turn back on both sides for the kit to work. I got mine at a local salvage yard for $50.

For 2wd that is. If you have a 4x4, and buy the 4x4 kit from Heartthrob (through LMC), the ram horns dump straight down in the middle. Therefore the exhaust pipes turn straight up.

And for what is worth, I've never had a problem with LMC.