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Hi All. I am new to the forum and am looking for some thoughts. I am restoring my dad's 69 Mach 1 mustang and ran into an issue with the cylinder heads while rebuilding the engine. The engine is a 428 CJ and when I was tearing down the heads I found some of the valves had guides installed at one point and and one of the intake valve bosses is split/cracked. I took the heads to my local machine shop for their opinion and to install new guides and hardened exhaust seats. They said since the head already has some guides replaced and with the split, it wouldn't be worth putting money into it and finding a new core. The heads are the original CJ 16 bolt heads (6090-N) and I am finding they are quite rare. What are your guy's thoughts? Is this a common issue and the heads are worth putting the money into or should I just pay the money for aftermarket edelbrock heads and intake?

Thanks,

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It looks like that intake valve must have "dropped" at one time and some damage was done. It looks like a new seat was installed and there is still evidence of some damage to the combustion chamber.
If you're not worried about originality a pair of aluminum heads would probably be the way to go. Another member here had a pair of 428CJ heads listed on the Philadelphia craigslist. $450 each or $800 for the pair.
 

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Nothing beats original parts. Unless you are drag racing, fix those original heads.
 

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I don't know and cant tell from the pic how dep that crack it, but it's the guide boss. This is a pic of a set I had ported and you can see most of that boss is gone.......

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In the last year my dad took his $400 set of cj heads to a machine shop along with some new 1 piece valves. By the time it was all said and done he had more in those heads than if he would have bought new and he had less performance. Cobra jet heads might be rare but they aren't that valuable, most will buy new rather than pay to refresh a set of heads anymore.
 

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In the last year my dad took his $400 set of cj heads to a machine shop along with some new 1 piece valves. By the time it was all said and done he had more in those heads than if he would have bought new and he had less performance. Cobra jet heads might be rare but they aren't that valuable, most will buy new rather than pay to refresh a set of heads anymore.
That is one true statement, I think for a few hundred more I could have been into a set of Blue Thunder heads......
However those heads are what makes a Cobra Jet a Cobra Jet, kinda lose those bragging rights without them......:cool:
 

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When buying used, you really never know what you are getting until it is magnafluxed..... at least you know what you currently have and what the issues are
 

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They can be fixed, the shop you took them to may not have the equipment to do them. You can replace the whole guide with a bronze one. There’s a shop not far from me that does a lot of that kind of stuff. It’s not cheep but that will make it original if that’s what your looking for..
 

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Me? I'd go aluminum, and save the heads to go along with the car if you ever sell it.
 
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