Replacing exhaust manifolds

[deerslayer79]

Has anyone here on GBO have replaced their exhaust manifolds on a 97 F-150,Mine are totally shot so I ordered a set of headers for my 97 and the mechanic said that he couldn't put them on without either pulling the engine or stripping down the front end to the frame.I asked why,he said that he would have to pull the heads off and re-machine the mounting holes to accept bolts because the studs are in Extremely bad shape.I am torn between letting him do it for the fair price of 1300 dollars or getting new heads and pre-mounting the headers and go from there myself,I have the ability,I just need the time to do it.

[goodwrench6710]

I have repaired broken studs on the right side manifold before on a F-150 with a 5.4 I believe (wasn't my truck). They are known for breaking studs. The wheel wells are plastic & can be removed without too much grief. You'll need a reversible right angle air drill like a Blue Point works very well & a good set of easyouts to remove the broken studs. If the threads are damaged, repair the head with timeserts, not heli-coils. As far as fitting in headers, I'm really not too sure how hard they are to install, some trucks are pretty tight. I done that job about 4 or 5 years ago & don't remember how much room is there & different headers can cause alot of clearance problems & fire hazards if routed to close to wiring. Good luck, I hope this helps you out some.

[rockbilly]

I have been kicking around the automotive maintenance arena for more years than I care to remember and I can't say I have ever seen a exhaust manifold that was "totally shot" unless someone did damage to them.   An exhaust manifold should never wear out.   What exactly happened to render them "totally shot?"

I put headers on my f-150, and also on a 72 Chevy that I was restoring.  I had leaks, loose bolts, warped headers, blown gaskets, and every other problem you can imaging.  I eventually went back to factory manifolds on the Ford, and did a rework on the Chevy headers to stop the leaks in them. 

In my opinion, unless you are hell bent on headers, I would stick with factory manifold, I think you will have far less problems in maintaining the vehicle.

[goodwrench6710]

The only problem I'm aware of with the Ford is the studs that hold them to the head break. I explained in my post how to fix it, not the worst job in the world & if you center punch them & drill them & use an easy out, they will come out. Be sure to drill the whole way through the stud, but don't drill way into the cylinder head, you'll know when you get through. It will come out & replace them. If the threads are damaged, repair the head, don't have to replace it. They even make repair kits for the sparkplug holes on this engine now.
I agree, headers are more trouble then they are worth! They warp, blow gaskets out alot, usually don't fit right, cause more under hood heat & potential fire hazard.
It's up to you, it's your truck.

[deerslayer79]

Thanks for the advice fellars.My 97 has 179,000 miles on it and has been a darn good truck,I have seen the exhaust manifolds and the phlanges are cracked in spots,and are a nice even deep brown color,from heat I guess.I think I may run it the way it is until this winter when I get my 3 months of vacation and do the repair myself.                                                                                                                                                                                                                                                              Thanks