My truck is a 73 F250 Camper Special w/390FE 2wd. I finished my exhaust off this last weekend. The only parts I was able to re-use was the factory Y pipe between the manifolds. This project included replacing the doughnuts on the factory manifolds and replacing everything back beyond the actual Y joint. New 2.5" single pipe back to a single 2.5" Thrush Turbo (17718) big body muffler and then over the axle and out the passenger side. Sounds great and is MUCH quieter than the rusted out 1.75" pipe and muffler! The Thrush has a great rumble at idle but disappears once you get moving.

I decided to check for leaks by having the girlfriend (brave soul that she is) hold a leather glove over the tail pipe while I crawled around and checked all the joints. To my amazement, the truck didnt die, but I could not find any leaks. I popped the hood and discovered both sides were leaking between the factory manifolds and the block. Leaking enough to keep it running at idle with the tail pipe completely sealed off! Time for manifold gaskets

I shot everything with Kroil and let it sit while I took my daily over to Napa and got a new set of exhaust manifold gaskets. I sprayed it down with more Kroil, heat cycled, and rapped on the bolts with a hammer when I got home. I repeated this process about 6-8 times until the afternoon when I decided to take the plunge. The first bolt snapped off at the block with very little effort. Great I decided to spray it and let it sit overnight and try again Sunday morning. I did the spray/tap/heat dance again about 4-5 more times and started in again. Second bolt sheared off with again, very little effort. The steel in the bolts is very brittle and crystallized, almost like they are cheap *** chinese grade X hardware store bolts. The head sizes are not consistent either.

So now I'm pretty frustrated and pissed off. I have an oil leak between the block and the back of the intake, so that needs to come off anyway. I know I have to pull the heads to get the broken bolts out (not enough room in there to get a drill/easy out in there) but I'm conflicted and looking for advice.

1) Pull the heads with the ex manifolds attached, deal with it on the bench.
2) Grind the heads off the ex manifold bolts, remove the ex manifolds and attack the remaining studs, possibly on the bench.
3) Keep going and see how many studs I break, remove the ex manifolds, pull the heads.
4) Any combination of the above.

I'm not 100% convinced the Kroil is getting past the manifold and working its way into the block threads, thats why I'm thinking about trying to grind off the bolt heads.

Anyone have any recommendations as to where to go from here? Thanks all, sorry for the long post.

 

The top bolts are VERY prone to breaking, no matter what you do. Bottom bolts are a crap-shoot of sorts, like any other engine.

I'd just break off the rest, in hopes that at least 1 or 2 top bolts *actually* come out. These heads aren't light, and the manifolds just add to that. Those bolts that break off, will do rather the head/manifold is still on the engine, or on the bench.

There's a few things you can do to help prevent future recurrance of this. Stainless bolts, helicoils (stainless inserts) in the bolt holes, lots of anti-seize, and making sure the top bolts do not protude out the backside of the port. Even doing *all* of this is not foolproof.

It's why I haven't even attempted to replace the blown exhaust manifold gasket on dad's truck yet. I even have a new set of headers, and no plans to attempt installing them in the near future. The passenger manifold has been in place for over 20 years. I only know one bolt hole that *won't* require drilling, the one that the bolt fell out of causing the gasket to blow out.......

 

Yep, was talking with a friend over lunch about pulling the heads with the manifolds attached. We determined (google) that assembled heads alone are at least 55lbs each, and probably another 10-15lbs for the cast iron manifolds. Add trying to lift that out of the truck and its going to spell disaster for my back.

Like you say, I've pretty much determined that I'm going to say "Screw it!" and see how many snap. I'll do everything I can to prevent it but it looks like breakage is inevitable. I also spoke to my engine guy and he has no problem pulling the broken bits out if I bring him the heads. He is about the only person I trust with this kind of stuff, and we go way back. I'm going to give ARP a call once this mess it taken care of and order me some spiffy stainless bolts or studs when I reassemble this pig. If the manifolds fall apart on me, I'll probably get a set of Hedman headers and be done with it. A pair of headers into a single 2.5" pipe is still going to be better than stock and shouldn't be that hard to plumb.

 

Also, someone might find this useful:

FE Manifold Removal

 

Rather than pull the heads it may be a lot easier to just yank the engine. That will also make the intake a hell of a lot easier and if you have any other leaks now would be the time to address them.

 

Don't think I haven't contemplated that. Of course, if the engine comes out I'll be tempted to do other things to this engine. Right now I'm trying desperately NOT to find a cheap Ebrock Performer 390 for the 600 cfm Holley 4160 that is sitting in my garage.

With me, its a slippery slope...

 

I just pulled my engine too. The manifold bolts were a major concern that I was not looking forward to, but to my surprise the bottom bolts on both sides came out with no problem, and the top bolts that weren't already fubar came out easily. There were a few that were smaller bolts with nuts behind them that someone in the past rigged up because the top holes were already missing threads. Of course, it was a bit easier for me since I had the core support out and could stand right next to the engine.

I've found with stubborn bolts it's easier to work at them very slowly. If there's resistence, move it just a little and let it sit for a minute while working on another one.

Headers are on my shopping list, since both my manifolds are broken. One of them, a big chunk of it came off with the bolt! The other one had a crack so big I could poke my screwdriver through it.

 

I was looking for a low cost intake, and ran across a like new performer 390 intake and a set of new-in-box flowtech headers for the amazing price of $120. I whipped out the wallet before the guy had a chance to change his mind.......
Wasn't really looking for headers, but at that price.......

 

That is a nice find for the intake alone! The headers just sweeten the deal If I can find a good used Performer 390 before this goes back together, I'll probably pick it up.

 

I think it would be easier to yank the engine rather than the heads. At least you'd save the expense of head gaskets. I just did my manifolds last week while the engine was out. It's pretty easy to grind the broken bolts flush with the block, then install heli-coil. I also had to do 3 inserts in the manifolds where the pipes attach. The hard part was finding th 25/64" drill bit required by the kit.

 

I don't have an engine hoist and head gaskets are already sitting in the garage ready to go. I'm probably going to start the tear-down this weekend. Watch for post after I screw up my timing and can't figure out where all the vacuum lines go

 

I'm probably going to be in the same boat with my new-to-me 70 Bumpside. The driver's side manifold is cracked and I dare not replace it now ('have a spare from my 390) because the engine has never been apart. The bolts are rusty, pitted, and look ready to snap if ya breathe on 'em. I'll deal with the body rust first and deal with the manifolds when the doghouse is pulled for a full engine upgrade, (manifold, cam, carb, headers), detailing, and a TKO 5-speed swap.

I got lucky with my 73 as the PO applied a generous amount of anti-seize and the bolts came out like butter... that's one of a few things for which I can thank the PO.. that and the new tires and brakes that were installed right before I picked it up.

To me, antiseize is the answer... do you know what's in it? Crushed glass!!...glass is inert meaning it doesn't react to environmental conditions like water or air (which with any ferrous material leads to corrosion/rust).

 

Drilling out broken bolts is always touchy, especially by hand. For one thing, the center of the exposed broken part is not the center of the bolt (or bolt hole).

I usually start with a small hole, and work my way larger until all that's left is a thin piece of the bolt. After that, I can often pick out what's left of the bolt threads.

So, knowing that, trying to do the work with the heads installed and the engine in the truck is likely impossible.

However, one thing that "might work", is a right angle drill (due to limited space), run it in reverse, and use a left-handed drill bit. Start with a smaller normal bit (drill running in normal direction) to make a pilot hole, then switch to reverse and use the larger left-handed drill bit. The heat and vibration will often loosen the bolt and if the left-hand drill catchs it, it can unscrew itself.

I'd try that if only a couple of bolts are broken off. As the numbers go up, it becomes more effective to yank the heads or the engine.

 

Do you have a digital camera? Take pics and mark lines with either colored tape or masking tape and felt pen.

 

THAT'S WHY ANTI-SIEZE COMPOUND IS USUALLY EITHER ALUMINUM OR COPPER BASED. Non-Ferous.