Bolts always breaking. Stainless headers too hot when towing...

Here's a solution. Did this, runs good, no more breaking. At least time will tell.

Stock bolts are Grade 8. Sometimes you can get 10.9.

Solution:

Grade 12.9 Bolts. (50mm and 55mm) with Bellville 5/16 Spring stainless washers. (Inkonel would be best if you can get a hold of them).

As you can't get studs in 12.9, this is the way I went. Use 8-9 washers in between for the heat shield. And use 2 Bellvilles side by side to create spring action. (When the bolts are expanding, spings are in place to not have the bolt break. When the bolts contract. Springs keep up the tension to avoid leaks.

Do not tighten very tight. Let the Bellvilles do their work. Photo attached.


Also to note, Lower thermostat to 180, and it'll save your old bolts, at least for some time!