Header bolt install prob

[mgwarrior350]

so i did the install today pretty easy not that bad but when I went to bolt the headers up with the stage 8 bolts part number 8909 they wouldnt thread right so i checked them and they were the wrong thread. I had some grade 8 in the right thread and size so i threw them on for now. Should I just leave these on there and just check them in a few days to make sure the didnt back out or is it really that much better to have the stage 8 vs the grade 8.

 

[mgwarrior350]

Also did i order the wrong ones the numbers 8909 and the box even says mopar viper v10

 

[BLWNSRT]

I've got the same ones in my truck part number 8909 the are 5/16 For the 8.0L v10 I have had a set of header bolts for my other truck boxed wrong. I would go back to where you got them and exchange them if you can. You don't want to have to replace a gasket because a bolt came out.