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I am going to get Stage-8 Header bolts. They come in either 1" or 3/4". I measured the depth of the hole in my Dart heads and they are 3/4" deep. My Flowtech headers came with 3/4 long bolts. But the header flange to the head is over 1/4" with the gasket, so I have a little over an inch with everything. (This is a loose measurement. I dont know how much the gasket will compress)
So should I stick with the 3/4" long bolts or will the 1" bolts work. The one inch bolts will give me the most bite, as long as they dont bottom out. Or would 1/2" of bite work in Aluminum. I am running Dart SHP Aluminum heads if that matters.
From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
bottoming out is the real problem...i am convinced most people who continually have leaky headers have this problem because of bolts bottoming out and they dont know it
There are several different advantages to using studs, but in this case I think the main one is that you practically eliminate the risk of stripping a thread in the head. Aluminum is pretty soft, and a stud engages every thread in the hole, spreading the load out. Even if you have to remove the studs to get the header on or off, they are still better. If you insist on using bolts, just measure the depth of the hole, and the thickness of the flange, and add the two measurements together. The thickness of the gasket and a washer under the bolt head will keep it from bottoming out. With a bolt, you really want to engage as much thread as possible without bottoming out.