Does anyone have any experience with the locking nut and bolt combination of Stage 8 header collector bolt kits? I see that Stage 8 has a lot of locking header bolt kits (with no nuts) for various makes, but where I need it is on the header collectors with nuts and bolts. There's surprisingly little info on the web about the nuts or how to use the nut/bolt set from Stage 8. Has anyone used it before? Is a separate nut also needed in addition to the threaded tab thing? Here's a page from Summit Racing showing that set:
http://www.summitracing.com/parts/stg-8950s/media/images
or at the very bottom of this page: http://www.stage8.com/offroad.html

Since metric sizes aren't available, the 3/8-16 is close enough to M10 with my headers.

Or does anyone have recommendations other than Stage 8 for a nut/bolt locking system? This is part of my annual header leak fix for my very frustrating TRD headers. This time I'm also trying Remflex graphite gaskets, which prefer lighter torque specs (14 to 20 ft lbs).

I have spoken with Stage 8 folks several times; mostly concerning their locking nuts for Dana axles.

They do make a quality product. I don't know about your specific issue but their techs should be able to answer.

So I tried these Stage 8 fasteners. I think they're great! I've driven a couple days with no header leaks or issues.

Now I can say there are no concerns about the strength of the nut thing. It's hard to see in the previous picture above, but the thing that acts as the nut is plenty thick - the threaded portion is probably the same thickness as a typical nut. No other nut or additional hardware should be used with it.

The length of the nut thing is just barely long enough to work properly at the large flange that's just in front of the cat. But they work!

It was probably faster for me to install these fasteners compared to regular nuts and bolts (or all-metal lock nuts) because I usually have to struggle with 2 wrenches or ratcheting wrenches in very hard-to-access areas with the headers. The Stage 8 fasteners only require one ratching wrench to tighten it.

I thought it was funny that the instructions from Stage 8 only mentioned their locking bolts. They didn't even acknowledge the nuts/bolts combo in this package.

If anyone else is reading this regarding TRD headers, it's fine to use the shorter 1" version of these. I had measured that I would need at least 1.25". But the way these Stage 8 nuts are, the threaded portion of the "nut" extends out a bit. It's possible to use less length on the bolt compared to regular nuts. The part of the nut happened to fit inside the hole in the flange, which also helped to keep it perpendicular to the bolt to start threading it. Then the bolt didn't need to be nearly as long, even with the thicker graphite gaskets.

I'm glad I cleaned out all of the old gasket material at any of the joints so the Remflex gaskets can do their thing.

This is just an update that I haven't had any issues with leaks or loose bolts since I installed the Remflex gaskets and Stage 8 locking bolts and nuts at the various pipe flanges. I'm very happy with it so far!

For reference, the part numbers that I used for the Remflex gaskets are 8010 (2 5/16" pipe flange with 2 bolt holes at 4 3/32" spacing) and 8018 (1.5" pipe flange with 2 bolt holes at 2.8" bolt hole spacing). I didn't get Remflex gaskets at the header connection to the engine, although they would make sense there too. I only installed the Stage 8 bolts and nuts at the various flanges along the pipe, not right at the engine exhaust ports.

For clarification, I have the older version of the TRD headers for the 3.4L V6. I purchased and installed my headers originally in 2001 or 2002. Mine did NOT come from TRD with the springs on the header bolts at the flanges, which is one of the distinctive features of the revised TRD headers (which I don't have). I don't know any specifics about the other TRD header design changes that TRD apparently made somewhere in 2003 or so. If you have the later version of these headers, the Remflex part numbers that I mention may or may not fit.