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302 V8 Header / Manifold Bolts Stuck / Help Please

Rustytruck

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Yep back in the day ARP made some small hex head big flange header bolts and we used to take a punch and dimple the headers to get wrench access. soft steel and strong when not rusted.
 

El Kabong

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x3 on allen head header bolts. It's far easier to fit an allen socket into the bolt than for a regular socket around a hex head in a tight place like that. I swapped to allen header bolts in the 70s & never looked back.
 
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CopperBronco

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Yep back in the day ARP made some small hex head big flange header bolts and we used to take a punch and dimple the headers to get wrench access. soft steel and strong when not rusted.
Yes, I got ARP header bolts for my new headers, stainless steel, 15% stronger than stage 8 bolts, and have a big flange and small hex on them. Excited to remove this problem moving forward!
 
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CopperBronco

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finally got one of my headers in. Been doing a lot of other projects and restoration with extra space in engine bay. How much clearance do I need around parts? I had long tube headers already, and am putting in SS Dominators from James Duff. Right now I have about an 1/8” between tubes and my passenger frame rail, only around 1.5” between tubes and my new high torque mini starter and it’s wiring (2awg and 10awg wires), and the headers touch my C4 auto trans dipstick tube like they did before. James Duff said they designed these headers to clear everything and assured me on the phone, but what Bronco project doesn’t have a few twists and turns, right?

I am thinking of adding a little fiberglass heat shield sleeves around electrical wires, and maybe squeeze some lava wrap around the auto trans dipstick tube. I do plan to replace that tube and trans lines when I redo my coolant system, but that might not be for another 6-9 months.

No idea about adding space around the Bronco frame rail, seems like not much I could do unless engine mounts were somehow changed which seems like a BIG job. Please educate me if there are other options.
 

DirtDonk

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Right now I have about an 1/8” between tubes and my passenger frame rail
Should not be an issue, as long as your motor mounts remain tight. The engine does twist, but our mounts are relatively rigid compared to a typical passenger car. So yes, that's close, but I think you're ok for now.

only around 1.5” between tubes and my new high torque mini starter and it’s wiring (2awg and 10awg wires)
Very close. I hate seeing that, but the good news is that the newer style starters are very resistant and that 1.5" is actually more than some.
I would not want the tubes that close to the wires though. Normally around town running might not see an issue, but a long uphill slog on a highway trip sometime can really put the heat down there even with all that extra air flow around things.

and the headers touch my C4 auto trans dipstick tube like they did before.
Another common thing, but another one I don't like. I doubt it's going to add much heat to your trans fluid, but it sure can make checking the level miserable!

James Duff said they designed these headers to clear everything and assured me on the phone, but what Bronco project doesn’t have a few twists and turns, right?
Exactly.

I am thinking of adding a little fiberglass heat shield sleeves around electrical wires, and maybe squeeze some lava wrap around the auto trans dipstick tube. I do plan to replace that tube and trans lines when I redo my coolant system, but that might not be for another 6-9 months.

No idea about adding space around the Bronco frame rail, seems like not much I could do unless engine mounts were somehow changed which seems like a BIG job. Please educate me if there are other options.
I think the shielding is a great idea. Best practice for sure. Sleeving around cables and tubes and hoses. If you can slip something over the starter, better still. Not the end of the world if not, but better if you can.
Not sure changing the gap to the frame is a thing yet. Is one side closer than the other? Maybe others have had that experience and can tell you their results. Seems like a tight gap on the passenger side is not a big deal, but tight on the driver's might be more of one. But here again, only if movement is sufficient. And ours are fairly tight under normal conditions.

Another area that headers mess with are brake lines and H-blocks and proportioning/combination valves. If you have a later prop valve located on a frame bracket, that usually puts it right in the heat of things. If so, I would move the valve anywhere but there.
Fuel lines are easy to re-route, but the factory one is not quite as close to a header tube as would make moving it an absolute necessity. However it should still be looked at and if a small heat shield would not take care of the excess, then now would be the good time to plan the move to a new location.

Paul
 
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CopperBronco

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Should not be an issue, as long as your motor mounts remain tight. The engine does twist, but our mounts are relatively rigid compared to a typical passenger car. So yes, that's close, but I think you're ok for now.


Very close. I hate seeing that, but the good news is that the newer style starters are very resistant and that 1.5" is actually more than some.
I would not want the tubes that close to the wires though. Normally around town running might not see an issue, but a long uphill slog on a highway trip sometime can really put the heat down there even with all that extra air flow around things.


Another common thing, but another one I don't like. I doubt it's going to add much heat to your trans fluid, but it sure can make checking the level miserable!


Exactly.


I think the shielding is a great idea. Best practice for sure. Sleeving around cables and tubes and hoses. If you can slip something over the starter, better still. Not the end of the world if not, but better if you can.
Not sure changing the gap to the frame is a thing yet. Is one side closer than the other? Maybe others have had that experience and can tell you their results. Seems like a tight gap on the passenger side is not a big deal, but tight on the driver's might be more of one. But here again, only if movement is sufficient. And ours are fairly tight under normal conditions.

Another area that headers mess with are brake lines and H-blocks and proportioning/combination valves. If you have a later prop valve located on a frame bracket, that usually puts it right in the heat of things. If so, I would move the valve anywhere but there.
Fuel lines are easy to re-route, but the factory one is not quite as close to a header tube as would make moving it an absolute necessity. However it should still be looked at and if a small heat shield would not take care of the excess, then now would be the good time to plan the move to a new location.

Paul
Thanks Paul, any advice on fitting my driver side header in? I can’t get it to go. My prop valve is up on driver fender as I already had long tube headers in. I’m afraid I’m going to have to rip off brake booster to slide them down in from above. I tried from underneath the Bronco but seems like C4 trans housing where it meets the 302 engine block is too narrow, making me think they have to go in from above. Also Duff won’t pick up their phone for 2 days, so not super helpful.
 

DirtDonk

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Sorry, no. Most of the ones I've been involved in went in relatively easy. And the ones that did not, got put in conveniently just before I got there, or just after I left!
If the engine moving would help, you can remove the mounting nuts from the frame tower on that side, loosen the other and jack up the engine so that it rotates away from the tight spot.
maybe...

Paul
 
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CopperBronco

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Sorry, no. Most of the ones I've been involved in went in relatively easy. And the ones that did not, got put in conveniently just before I got there, or just after I left!
If the engine moving would help, you can remove the mounting nuts from the frame tower on that side, loosen the other and jack up the engine so that it rotates away from the tight spot.
maybe...

Paul
Fit headers in, just had to jack up and separate axle from frame and unhook driveshaft at the axle real quick and popped right in. Thanks for all the help! All you guys saving me as I learn Broncos.
 
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CopperBronco

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Sorry, no. Most of the ones I've been involved in went in relatively easy. And the ones that did not, got put in conveniently just before I got there, or just after I left!
If the engine moving would help, you can remove the mounting nuts from the frame tower on that side, loosen the other and jack up the engine so that it rotates away from the tight spot.
maybe...

Paul
So one other complication… the front drive shaft almost touches the header… maybe an inch of space, 3/4”, is this enough clearance? I see some folks heating up there headers by turning engine on and then prying / bending with a 2x4. I have good clearance near the driver frame rail and brake lines so that’s good!
 
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CopperBronco

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One other clearance question with exhaust… is 1.5 to 2” space between after muffler / tail pipe & gas tank enough? See photo… no mention in install videos of minimum clearance besides make sure things aren’t touching.
 

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DirtDonk

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Looks like more than enough at the gas tank. Sure it warms things up a little, but by the time you get to the tail pipe it’s not usually hot enough to do any real mischief anyway. And if there was a concern you could always create a small heat shield/baffle to block some of the heat before it gets to the tank
 

DirtDonk

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Got a picture of the front driveshaft issue? Depends on what plane that proximity is in.
If it’s not going to physically hit during suspension movement, then I don’t think the heat is a big issue in and of itself. Not unless it’s right next to a joint that is.
 

DirtDonk

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Regarding the Stage-8 header bolts, I think most of us bronco vendors carry them, or something similar.
Or used to anyway.
 
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CopperBronco

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Sorry for REALLY late reply here. The driveshaft and exhaust almost touch when I raise up my Bronco's frame, an then lower the axle to create space when working on it. But they touch and can slide past one another with a light rubbing. The only solution I've seen online is that people get the headers real hot and then take a 2x4 and bend their headers... makes me worry it'd bend the bolts in the block too... but seems like the going solution. For now I think it's fine and I haven't heard any hitting while driving around. I'll watch the cerakote coating to see if it's hitting while driving the next few weeks.

At normal resting position I have about 3/4" of clearance between the exhaust and driveshaft.
 

Rustytruck

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a couple of thick washers between your motor mount and the passengers side engine block may help some. the rear cross member at the tranny loosen the bolts at the tranny mount and the frame mount you can usually do a little prying to move the tranny over a little. weare talking little bits here and there but they all add up. Make sure you get all the clearance around the side of the engine you can especially heater hoses and any thing you bolt in there airflow is key around the sides of the engine.
 
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