DarkKnight

Im looking for 1&1/4" stainless header bolts for my 94 LT1. Headers have a 1/2" flange so I think 1" bolts are a little short.

Thanks for the help.

gaedbo

I know a lot of places where you can find fasteners, but a company called McMaster Carr will have them plus tons of other things you may or may not ever need.

There assortment of fasteners is really good. McMaster-Carr

DarkKnight

Will ARP 712-1250 work?

gaedbo

I believe they are 3/8-16 thread bolts, and not 5/16-24 like the 712-1250 that you are asking about.
The first fraction is the diameter of the bolt, and the second number is how many threads per inch, the length is determined by measuring under the bolt head to the end of the bolt thread.
You might want to remove one of yours to confirm size and length from the easiest access, to make sure.
I also believe that some of them are different lengths, because some use a spacer, or will have a stud.
I am going by what I have been reading, I have not had to replace mine, so I can't confirm this.

DarkKnight

Yeah, I don't really know how to read all that stuff about bolt sizes and dimensions. That's why am trying to get a little help. The stainless headers I bought that have a half inch thick flange so the three-quarter bolts are too short and I'm afraid that even 1 inch is still too short.

I was referred these:
Stage-8 Locking Header Bolts 8911B

gaedbo

Initially I thought you knew the sizes, but were just looking where to buy. I would suggest you re-post your Thread like this " Injuneer or Shbox I need help with Header Bolts Sizes"
If anybody can help it would be either one or both of those guys with detailed anwers.
Make sure in your explanation you give as much detail as you can so they can give you the best answer.

Injuneer

LT1 uses 3/8"-16 bolts. You don't want to buy general purpose bolts from a hardware store. Buy bolts specifically made for headers. They will have a smaller head, allowing them to fit in the tight space available, with the ability to actually get a wrench on the head. I use ARP stainless with a 6-point head.

gaedbo

Thanks Injuneer, I knew you would know the answer for him. I am guessing he may contact again wanting to know the lengths.

Injuneer

I think I remember Rob/Shoebox mentioning that the stock bolts are ~1-3/16" long. But some of the stock bolts use spacers.

DarkKnight

This is great information, thanks for all your help!