Advice needed on manifold repair

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Nothing ventured, nothing gained.
If brazing fails, then The silver lining is that I got some brazing experience.
Your money, your dream.
Anything can be fixed, only you will know if it's worth it.
I think I would spend my money and time in a different direction
 
I have very little in it, $150 to fix would be worth it to me
You'd have more than that in it labor prep-time & materials, let alone actually welding & re-machining. I wouldn't touch it, 'cause I wouldn't steal Your money, it ain't worth it. There have been a bunch of good cast SB intakes here on FABO for that or less.
You aren't "giving up" on anything, You'd be making a wise decision to move on. If it was on Your Pappy's street racer & had some sentimental/personal tie to You, I'd certainly keep it...but still wouldn't fix it.
Good luck with Your call, peace!
 
If that was just a crack and a manifold worth fixing and you were capable of drilling the end of every crack it’s doable. But that thing is crack in many different directions and even after welding it you would have to magniflux it to see if you caught everything. Do yourself a big favor and write it off as a learning experience.
Great advice, we have become a throwaway society, buy cheap Chinese products, replace em every few years. I still believe in the good ol American craftsmanship from the past.
 
I get a charge out of asking for opinions. Apparently scrapping it wasn't what he wanted to hear.
 
I would not spend a dime to fix that. But If I were bored I might try fixing it myself. When I worked in an exhaust shop we welded exhaust manifolds. I would v the cracks way out. Heat the entire manifold as hot as I could get it. Heat the areas to be welded red with a torch and then weld up with a plane old mild steel mig wire.
The challenge is keeping the entire thing hot enough while the temps equalize across the entire part. Then throw it in my old garage oven with it as hot as it will go for a few hours then back the temp down over a day. My suspicious is this is far more complicated with stresses pulling in a lot more directions than an exhaust manifold.Likely wouldn't work
 
Yeah that manifold is junk, I was buying those 340 intakes at the swap meets for 100 a pop, and they were good.

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You've gotten lots of good advice above.
Personally, i wouldn't spend ten minutes/ten cents on that mess.
If i could get a buck for it scrap weight......, id take it.
I've got a 33 Imperial straight eight exhaust manifold that is in similar condition (actually,, much worse). It's worth it to me to get it fixed, they don't grow on trees.
But a new, better, intake for a small mopar, is a five minute phone call and a credit card away.
 
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I'd throw that crap in the dumpster and get another one. They're everywhere.
 
If I had a lot of spare time I may weld it up for practice. Regardless of how it turned out I would scrap it when I was done. I would not run it on any car.
 
Got this in a swap

lots of cracks

Wasn't too interested till I found out it's 68-70
340.

Isn't this the best 340 manifold or was the 71 better

Looks like someone attempted a jb weld patch on the back of the manifold

I have never seen a manifold crack this extensively

Not concerned that it will appear patched

Was this one of the manifolds Mopar copied or vice versa

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Cmon man, you got to be joking.
 
I think that manifold was dropped onto concrete to have that many cracks. But whatever.

You certainly would not braze it, for a couple of reasons:
- It is under continuous tension
- braze loses strength at higher temps.

Remember that boat anchor you dreamed about owning.....
 
Its A great manifold that froze and is now Junk.

That sucks.
 
Junk. You will be chasing issues with that one forever.
It truly is JUNK. There are plenty of 340 manifolds out there. I sold a very nice one about 2 years ago the third time I listed it for, I think, $125. The first two times I listed it I started heard nothing.
FWIW, Take the loss and move on. It's like this. If you had a 69 Roadrunner with the Matching number 426 Hemi in it, and the Hemi had a lot of freeze crack damage that could be repaired for $8,000, then spend the money. You have a part that is not at all rare. Place an add in the parts wanted section.
 
There's no distortion on the intake port crack, or other shift that would require machining. I'm thinking about about what CH 1 II said about brazing it. I had good luck with that before. I have practically nothing in it.
Having an engine machine shop we see all kinds of things people want repaired for rare engines where parts are not available. After you add up the cost of material and machine work you'll have more in it then its worth. And then will it last through heat cycles after you waist a gasket set. Will it leak coolant into your fresh engine? Will it suck air and lean the engine out? You won't know until you waist more money.

Do you actually think that intake is worth the money you'll have in it. If you paid more then $5 for it you should take your losses and move on. The intake is junk. Spray welding would be the proper repair. That material alone would cost more then a new intake. Scrap is $9.00 a 100 lbs. so you should be able to make money if you got it for next to nothing like you said. What did you actually pay for a chunk of cast iron? That's the Question I would like an answer to.
 
He thinks everyone's negative thoughts on that "precious" intake is a challenge. That being said, if he wants to put $150.00+ into a piece of junk, let him. If he "is" foolish enough to take it on, he can't say he hasn't been cautioned away from it. Personally, no matter what year SBM intake it is, there are still plenty of them out there, and not to mention aftermarket intakes that work just a well and/or flow much better. If he wants to take a chance of polluting whatever engine he puts it on, again it is his money and labor. As I stated on my first post, he's going to end up chasing it down the rabbit hole.
 
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