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The bolts are so close to the tubes that I can't fit a socket or wrench on them. I don't know how they were ever installed. On some of them, the primary tube wraps right over them, so even if I could loosen it, I'm not sure there'd be room to back it out the whole way. They had to go in somehow. How do I do this? Bad pictures to show examples below.
I cut the heads off of my exhaust manifold bolts that were rounded at the top. I used a dremmel with a cutoff wheel. Then I was able to remove the bolts with a vice grips (after manifolds were off). It was surprisingly easy but they were exhaust manifolds which have less of a "shoulder" than your headers. The dremmel cut-off disks work great but you cannot apply any lateral force (only cut perpendicular to the shaft) on them which makes this a little trickier. The idea is to cut all "bolt head" and no header but if you did impact the surface of the header "mounting plate" I don't think it would matter much. Because the flange or "mounting plate" of the header is wide, you have to come in at a slight angle instead of cleanly cutting off the head. The cut-off wheel mandrel is not quite flush with the wheel (sticks out just a little). I got through 2 bolts with one wheel and started to get bold or stupid and started applying some lateral force which immediately shattered the wheel on the third. The good news is they're cheap.
Now that you have studs sticking out, does the header "clear" by coming straight away from the engine or do you have clearance issues..... in which case this strategy suddenly gets a lot more complicated... cutting more stud off between the head and the header after establishing some clearance.
Also... have you considered using a tiny box wrench set? I know Craftsman used to make a little pouch of open end/box wrenches...
Also, also... hit the bolt head with a torch. Make it cherry red. Make sure to shield the head from the flame. Aluminum is kinda susceptible to that. Heating the bolt seems to break the bond between the head and the bolt if they're corroded and stuck.
When you're done with this mess (you'll get there!), consider different headers. Those things look like challenges you don't need.
Good luck!
I second on using a ground down (preferably curved) box wrench. You can pick up a cheap set at harbor freight and grind the outside and it should just barely slide over the head. Some of those bolts won't come out completely until you have the rest loosened. When you make the long tube swap consider switching to a bolt with 5/16 head for better access.
LT1 owners can be so stupid sometimes. After you get that **** off, get yourself some hex 3/8x1” or 5/16x1” ARP header bolts and you’ll never have to deal with that type of **** again.
as far as getting the bolts out if they're longer than the space between the primary and the bolt hole, you're going to have to pull the header off as you unscrew the bolt so the header and bolt come off together, then you should be able to angle the bolt enough that it comes out of the header.
Are you keeping/selling the old headers? If not I'd just cut the old pipes off with a Sawzall then unbolt the flanges.
i have considered that! Up until now I’ve been too afraid to get a sawzall in there with all the wires and fuel lines. It’s pretty tight. I have some cheap wrenches I can try to grind first.
LT1 owners can be so stupid sometimes. After you get that **** off, get yourself some hex 3/8x1” or 5/16x1” ARP header bolts and you’ll never have to deal with that type of **** again.
Or just use studs instead of bolts...Then you can just slide the headers onto the studs and then you don't have to fight with lining up the headers bolt holes while trying to start the bolts.....
If you can, try to loosen that bolt before any other. That way the flange will still be tight onto the head and there won’t be as much pressure on that bolt to get it loose. I’m not even sure how to get a 12-point bolt loose in those close quarters, but I’m sure you can figure something out. Once it’s loose, take all the other header bolts out and then loosen that bolt so the flange follows is out. That way you don’t have to worry about the bolt head butting against the primary. It’s also possible that bolt is ground way down and is only hanging on by a thread or two so the primary isn’t an issue.
Originally Posted by two lane blacktop
Or use studs instead of bolts...Then you can just slide the headers onto the studs and don't have to fight with lining them up while trying to start the bolts.....
There’s an easier way as long as you use a Fel-Pro 1406 or equivalent where the gaket has openings on each end so you can install the header first with bolts on both ends of the flange and then slide the gasket in.
The way I do it is I hold the header up and find the easiest bolt hole to start a bolt. The header is then suspended so I can easily put in the front/back header bolts. Once those are in, take out the initial bolt, slide the gasket in and then put in the rest. Then torque them down from the inside out.
I was able to get the passenger side out after grinding down a wrench, so thanks to those who suggested that idea. I never would have thought of it myself. I still have to do the driver's side and, of course, it's a different size bolt on that side so I have to grind down another wrench.
02-02-2019, 02:07 PM
How am I supposed to remove these header bolts? 
