Exhaust on a 77 fj40

[curtislow]

I'm in the neverending process of restoring a 77 fj40 to a good driver quality cruiser,so we're not dealing with a show quality truck but a fairly decent frame on rebuild.
I'm sitting in my garage taking a break while doing the second side of a knuckle rebuild and contimplating my next project which is the exhaust.
I have a stock skidplate sitting hung on the wall and I'd like to use it with the header exhaust that I now have that would end up below that skid plate , I think and kinda know that the original pipe went through skidplate and then out above the rear axle exiting behind the drivers side tire. Has anyone routed ir differently.I still want skidplate protection.
6 into 1 header on a 77 2f motor. Thanks in advance.

 

[Fast Eddy]

I'm pretty sure it went under the skid plate originally. If you're going to wheel it put it over the top. I had to bend my stocker a bit to get it to go over, but not much.

 

[65swb45]

I routinely notch the leading edge of the skidplate to avoid having a harsh angle on the pipe.

 

[Solace in Solitude]

I don't know what brand headers I have, but they are a 'double-tri'... they are designed to feed to a collector that routes above the skidplate.

When I had the exhaust replaced, I reused the headers and the collector... the exhaust experts didn't think they could make it fit above the skidplate, but they did.

Sorry, I can't get pictures for two more months... but, you should be able to make it work... especially if you 'notch' it as Mark suggested.

EDIT: I think the original exhaust went back behind the rear axle, then took a sharp turn to the passenger side, before exiting at the back of the truck. Be sure you keep your's exiting behind the driver's side tire, if ever anticipate adding an auxiliary tank.

 

[KingAir Driver]

I'm in the same situation with my '77. PO replaced exhaust, it currently runs above the skid plate, but muffler is just aft of it. Would love to see what you do.

 

[curtislow]

I'm in the same situation I with my '77. PO replaced exhaust, it currently runs above the skid plate, but muffler is just aft of it. Would love to see what you do.

Thanks for the replies. I can't imagine it not being above the skidplate where it would surely get squished if you did any kind or wheeling.
It makes sense to knotch the front edge, I'm going to be talking to the muffler guy soon and would like to get it up and out of the way. Has any one used spacers to bring down the plate? And lastly, I believe downey used to sell a heavy duty plate. I don't know if this plate gave you more room to route it above,does anyone know?

 

[emac]

I routinely notch the leading edge of the skidplate to avoid having a harsh angle on the pipe.

Exactly what I did. FWIW, I really couldn't find a quality header and ended up going with one from JToutfitters and had it machined to the intake to make sure it wasn't going to leak. Fingers crossed, it is doing fine. Several good threads on leaking headers!

 

[Catfish28]

Not sure it helps but here is what the stock exhaust does on my 78.

 

[emac]

A bit hard to see, but I found a picture of my rig that shows the exhaust above the skidplate.

 

[Solace in Solitude]

Thanks for the replies. I can't imagine it not being above the skidplate where it would surely get squished if you did any kind or wheeling.
It makes sense to knotch the front edge, I'm going to be talking to the muffler guy soon and would like to get it up and out of the way. Has any one used spacers to bring down the plate? And lastly, I believe downey used to sell a heavy duty plate. I don't know if this plate gave you more room to route it above,does anyone know?

I think Jim (@Downey ) may still sell it... Maybe he will chime in...

 

[65swb45]

I bought one of Downey's last skidplates years ago on spec for a good customer who didn't follow thru. I've never advertised it, but I have ONE. Boxed and ready to ship. 818-953-9230 to follow up. No PMs please.

 

[Pete]

Don't notch your skid plates boys! Use the notch that's already there for the PTO shaft. Find an independent local muffler shop - the kind that has the tin man out front made out of discarded mufflers and pipes - and have them custom bend a pipe to go above the skid plate. I've done this on 3 Cruisers, one skid plate got notched because the guy was lazy and I wasn't there to stop him. It should run above the cross member that's just behind the skid plate.

 

[Trialsallday]

I bought one of Downey's last skidplates years ago on spec for a good customer who didn't follow thru. I've never advertised it, but I have ONE. Boxed and ready to ship. 818-953-9230 to follow up. No PMs please.

Still got this skid plate by any chance ?

 

[shelfboy1]

the early cruisers had it above the skid plate some time later on it was below .mine didn't last long below but back then you could buy the early style exhaust and route it above

 

[65swb45]

Still got this skid plate by any chance ?

Sold.

 

[cruiserboy14]

does putting the exhaust above the skid plate create any excess heat? and if so how do you deal with it??

 

[Living in the Past]

Can't help but add heat. Adding a heat shield like the area just behind the skid plate and in the back like your 77 should have would help. I run PTO winches and that makes it harder to run the exhaust above the skid plate. 1/79+ a CAT was adding and exhaust fan outside the frame. 79/80 exhaust was run under the frame up front.8/80+ it was run above the frame with a heat shield on the firewall. I.like that way the best. Moves the exhaust away from the transmission and transfer case. Also exhaust is not boxed in above the skid plate.

 

[65swb45]

Can't help but add heat. Adding a heat shield like the area just behind the skid plate and in the back like your 77 should have would help. I run PTO winches and that makes it harder to run the exhaust above the skid plate. 1/79+ a CAT was adding and exhaust fan outside the frame. 79/80 exhaust was run under the frame up front.8/80+ it was run above the frame with a heat shield on the firewall. I.like that way the best. Moves the exhaust away from the transmission and transfer case. Also exhaust is not boxed in above the skid plate.

As someone who wheels their truck moderately hard, I cannot accept the 79+routing system that puts the headpipe crossing under the frame right behind the ‘slide zone’ of the left front spring. Or the way the cat hangs out exposed outside the frame.

I have crushed pipe in the Little Sluice Box of the Rubicon and had to hacksaw the system open just to get moving again.

I just got done showing @fjl40 the hoop-type skidplate I run on my 40 and 45, inspired by @fc187. Better protection than stock, and better ventilation than stock, Downey or IPOR.

There are pics of it on the forum; somebody with better search skills can probably find a link.

 

[Living in the Past]

As someone who wheels their truck moderately hard, I cannot accept the 79+routing system that puts the headpipe crossing under the frame right behind the ‘slide zone’ of the left front spring. Or the way the cat hangs out exposed outside the frame.

I have crushed pipe in the Little Sluice Box of the Rubicon and had to hacksaw the system open just to get moving again.

I just got done showing @fjl40 the hoop-type skidplate I run on my 40 and 45, inspired by @fc187. Better protection than stock, and better ventilation than stock, Downey or IPOR.

There are pics of it on the forum; somebody with better search skills can probably find a link.

That is why I said I perfer the 8/80+ routing which is above the frame. This is the plan for my 79. Working on getting the header pipe. I already have the stock heat shield for the firewall. I run PTO winches and really too tight running exhaust above the skid plate. Have a PTO while not leaking the exhaust did melt the housing. Don't think the gear oil needs any extra heat in AZ.

 

[65swb45]

I will be a little more clear: for the 99 percent of people who are NOT running a PTO setup, an exhaust pipe inside the frame with a custom tubular skidplate is the best option.