Doug Thorley Header Installation

[lazyguy]

I just got my headers for my '75 J-10 and was wondering if anyone had any suggestions and or a write up on how to install them. The directions that came with the headers are for '80 and up. Also the slip fit section of the y-pipe, are you supposed to weld it shut when the headers are all situated or just leave it or put an exhaust clamp on it? Lastly, I'm just wondering what is better, to use the gaskets that came with the headers or the Remflex gaskets. What do you torque the header mounting bolts to depending on the gaskets. Other than that, the only thing I can say is that those headers are awesome and our host here sells a good product.

[Brent]

Use the Remflex gaskets they are far superior to the DT gaskets, the torque specs are on the back of the Remflex pack, I believe 16-18 ft/lbs. You can eyeball it too, crush the gasket halfway. Plus you never have to retorque the Remflex gaskets!

They are pretty simple to bolt up:

1. Loosely bolt up the headers to the head
2. Loosely put the y-pipe on
3. Tighten from the rear to the front (do the head last)

That should be it. On the slip fit connections they seem to seal just fine but if they don't run a clamp on them.

Thanks!

[lazyguy]

thanks. For installing the headers, I was going to put them on the engine and then drop the engine in the bay. Will bolting on the y-pipe after the engine and headers are all situated and torqued affect the header/gasket sealing?

[Ryan]

it's best to install the headers after the motor is in, as when you are trying to adjust the location of the motor, the headers can get damaged. Also, it makes it harder to access the motor mounts when they are pre-installed. Once the motor is in, and the headers have been installed, leave the bolts for everything loose while you are connecting the rest of the system. Only after everything has been connected and all bolts left loose should you start slowly tightening everything up.

[lazyguy]

Thanks for the help I'll try that then. Are there any special tools to tighten those headers up? I was looking at them and looks difficult to get a ratchet in there due to the angles of the primary tubes.

[Ryan]

a box-end / open-end wrench is what I use the most. I just take my time and am VERY careful not to round the bolt head. I plan on about an hour or so to fully tighten everything.

[lazyguy]

Can you post pictures of how the doug thorley y-pipe runs underneath a 70's J-Truck because I began to put it together today and the y-pipe seems to be routed under the driveshaft? Did I get sent the wrong parts or is this the correct routing? If it is, won't the driveshaft hit the y-pipe when/if the truck is lifted or articulates the suspension heavily?

[Ryan]

the earlier trucks from 72-79 did have the y-pipe routed underneath the driveshaft, and was a funky design. You should still have clearance after a lift and during flex, but I would HIGHLY recommend doing a static flex test in the garage or in a non-wheeling spot and double check clearance before wheeling it.

[lazyguy]

I will post some pics of it mounted up. Maybe that's a better way to explain it. (Here are the pics.)




Is that the right routing for the Doug Thorley y-pipe?




Do these headers and y-pipe require a heat riser? I thought thought they eliminated it. If they do require it how do I order the one needed for the headers?

[83AbramsTank360]

It's interesting, I'm working on a '75 J10 that looks JUST like that one AND I'm having the same issues with Doug Thorley Headers...

[Ryan]

the DT headers do allow for eliminating the heat riser (that is also why we have the pull down menu on the webstore to see if you need one or not). The way to install these is to have everything bolted together, but loose (including / especially at the heads). Then, once everything is loosely bolted together, start tightening up everything starting at the back and working your way forward.

[lazyguy]

When I ordered the headers, I selected no for the heat riser. But if I try to bolt the y-pipe together the passenger header/y-pipe flanges do not line up right. I have everything loosely bolted together. In the pictures I posted it looks like there should be a heat riser to fill that gap. Is it possible I got the wrong y-pipe? The order number for the headers is #23116

[Ryan]

I'll have Brent double check inventory to make sure you got the right one.

[Ryan]

Brent is checking with the mfr to make sure something didn't change w/o them letting us know.

[lazyguy]

thank you