Insane3D said:1" may work, but .75" is stock length. Be careful not to screw up the threads with a longer bolt...
IMO, locking bolts are a waste of $$$ anyhow...
If you simply snug them up a few times after a few heating/cooling cycles, they will stay put. I used ARP 12 point SS header bolts, and they are much nicer than the POS Stage 8 locking bolts they replaced. The FMS and the Stage 8's will rust FYI...
Maryland Stang said:Most aftermarket headers use a thicker flange hence the 1" bolt. I have them on my Flowtechs.
Stage 8s have been recently redesigned. Much nicer now. And I have no rust on my old design Stage 8s.

jrichker said:In the day of my youth I was an aircraft mechanic, so I still do some things that way. I got some 1" long 3/8" course thread, stainless steel allen head bolts for my headers. The bolt heads were drilled with a #52 drill bit (about .040) using a drill press and lots of WD40 to cool the bit. The head is drilled with the holes in a cross pattern at 90 degree angles to each other.
I bought a 5/16" Bondhus Balldriver Allen wrench, it works like a universal joint. You can tighten up the Allen head bolts at 15-20 degrees off center angle and still get everything tight. Cut the "L" part off the wrench with a cutoff wheel and stuck the straight part in a Allen socket. This works great, cause the Allen heads are smaller than even the 12 point bolt heads, and with my fancy tool I can tighten them up with a torque wrench.
Torque the bolts down and pull off about 12" of .032 stainless steel safety wire. Thread the wire through 2 holes, or just one if the other one is blocked by the header pipe. Pull the wire through until the ends are even. Twist up about 2" with your handy-dandy safety wire twister pliers, making sure that the wire pulls the bolt tighter as it routes across the header pipe. Make sure the twist ends at the wire hole in the next bolt, and that it pulls the bolt in the tightening direction. Thread it through and twist up about 3/4"of wire on the other side of the hole and cut it off evenly. Fold it over about midway so that the sharp end doesn't stick you.
Another trick...
I have a cheap fix - get some 18-20 gauge sheet steel and cut 16 pieces of metal into strips 9/16" wide x 3/4" long. Drill a 3/8" hole centered side to side and 1/2" from the end of the metal strip. Use this strip as a washer, with the tab positioned pointed up towards the rocker covers. When you finish tightening the bolts down, take a screwdriver and a hammer, pry the tab up and then beat it down tight against the flat sides of the bolt head. If you use hex head bolts they will never back out again. You may have to play with the dimensions a little to clear you particular set of headers, but it will work good.
Insane3D said:As for the Stage 8's, I'm guessing your car doesn't see winter? My Stage 8's heads were so rusted, I needed to soak them with PB blaster for a day because they had rusted to the header flange on my old POS BBK shorties. The were heavily rusted, and even if they "redesigned" them, unless they are stainless now, they will rust eventually..
I went with them years ago when I did my BBK headers, and those clips were very tedious to work with, and made a simple header swap much more time consuming, not to mention losing clips down in parts of the K member. Of course, Stage 8 doesn't give you any extra locks, so if you lose one or two, you are SOL unless you want to buy a new kit.
Anyway...just my experience and preference...to each his own.
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