Exhaust manifold bolt questions

[smsag04]

I removed my exhaust manifold to repair a bad gasket and found a few questions to ask.

1) I had to cut the top bolt on the #5 cylinder. It has a nut on the back side. Is it supposed to be that way or was that originally threaded into the block?

2) I was planning on chasing the threads in the block and replacing the bolts with some new grade 8 hardware. Are the threads just 3/8" UNC?

3) Since the manifold didn't use a gasket originally, should I go back with some Permatex Ultra Copper or use a gasket?

Also, I found something interesting. I knew that the engine wasn't original so I looked up the casting numbers. The head is C1UE, best I can find is that it's a '61 Econoline Van. I bet not many Mustangs have that!

 

[Bort62]

1.) No nut. Something's been altered - no big deal.

2.) yes.

3.) C1 means you either have a 144 or 170 head. Bummer.

 

[pedal2themetal45]

Bort62 C1 meand 1961....

yes I'd use a gasket...
tim

 

[fordconvert]

I have been told that grade 8 hardware is too hard to use for cast manifolds because it doesnt expand properly. It also makes it a PITA to get them out if there is a problem. I like the ramp-lock bolts that some of the vendors sell, I guess it was a Ford thing starting in the late 60's.

 

[simon]

Over here it is fairly popular among classic car enthusiasts to convert the exhaust mainfold bolts to studs and copper nuts.

However, they like to discard the gasket, but rely on exactly machined mating surfaces and a thin bead of high-temp copper silicone.

Personally, I'm not sure yet which route I'm gonna take with my heap.

 

[falcon fanatic]

Mike sells some very nice metallic gaskets that I would recommend. As for bolts, there is not need for grade8, but I'd consider stainless since that will guarantee they won't rust in there.

 

[aahsac]

I used grade 8 bolts because they were cheap and local and my originals were junk. I used anti-seize, mainly so I could see everywhere I touched like when I smear it in my nose, ears, etc. I used a Felpro gasket and I have no exhaust leaks. I put a wrench on all the bolts ofter a couple heat cycles.

I have used the no-gasket approach for years on my motorhome. It's a 455 with Thorley headers and proper header bolts. No leaks there too.

 

[Bort62]

Bort62 C1 meand 1961....

yes I'd use a gasket...
tim

Yes, and in 1961 they only made 170's and 144's