High-mileage 915 J heads... can they be fixed?

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MopaR&D

MopaR&D

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So it's not an A-body but since I got my 1972 D200 with a 360 running it always idled like crap even with a nice 4-bbl conversion and full ignition tune-up. Well last night I was in the process of installing some headers and broke the rear exhaust manifold stud on the pass side head. I had a feeling the exhaust valves were sunk based on how it ran and I could see the valves look burned from the open exhaust ports. Got the pass side head off and sure enough, all the exhaust valves are sunk to varying degrees with one almost 1/8" down.

Question is is that repairable? Also will I need new exhaust valves? I'm kind of leaning towards just finding another set of 360 heads in good shape to throw on; I just want to get this truck running again so I can use it to help move my stuff to my new place in a couple weeks. I'm not trying to build a performance engine either, the ultimate goal for this truck is a 12-valve Cummins diesel swap anyway so I don't want to spend any more on this current 360 than I need to just to keep it running reliably.
 
yellow rose said:
If the heads are fractured they are easily fixed.
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I take it you mean if they AREN'T fractured? lol...

Guess I'll call around to some machine shops on Monday. Any idea on the cost for fixing the seats? Gah I always get super anxious when something breaks lol I want to know immediately how much it'll cost and how long it'll take to fix it, hard for me to be patient about this stuff especially when it's a vehicle I kind-of rely on.
 
Rent a moving truck when the time comes and park the truck till it's time for the swap..
 
MopaR&D said:
I take it you mean if they AREN'T fractured? lol...

Guess I'll call around to some machine shops on Monday. Any idea on the cost for fixing the seats? Gah I always get super anxious when something breaks lol I want to know immediately how much it'll cost and how long it'll take to fix it, hard for me to be patient about this stuff especially when it's a vehicle I kind-of rely on.
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Yep if they are NOT fractured my bad.
 
Rock Auto has nice reman heads available for '76 D200, 587 heads pretty much same head as your 915 Js.

They do a really nice job on the reman work, ship out in plastic containers so you can ship your cores back in them and get your core refund back.

Their 72 915 J heads are out of stock now.

Screenshot_20200718-213536_Chrome.jpg
 
Rock Auto wants your vehicle VIN number for the heads1 year warranty. If you are getting heads from a different year 360 you can just put in "11" zeros for the VIN number and the order will go through.
 
George Jets said:
Rock Auto has nice reman heads available for '76 D200, 587 heads pretty much same head as your 915 Js.

They do a really nice job on the reman work, ship out in plastic containers so you can ship your cores back in them and get your core refund back.

Their 72 915 J heads are out of stock now.

View attachment 1715563730
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That looks like a good option, I'll keep that in mind depending on how costly it'll be to fix the heads I have.

Although my lease at my new place will start in August there's no rush to move out of my current place since it's my parents house lol. But I don't want to wait longer than I have to.
 
MopaR&D said:
That looks like a good option, I'll keep that in mind depending on how costly it'll be to fix the heads I have.

Although my lease at my new place will start in August there's no rush to move out of my current place since it's my parents house lol. But I don't want to wait longer than I have to.
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It will cost between 400-8-- bucks to have those heads properly repaired....possibly more. They will need guides as well, I am sure. Guide and seat work is not cheap. Add up guides, seats, valves, springs, retainers and valve locks. Then the labor involved. It's going to get expensive pretty quickly.
 
Last edited:
I agree, at minimum you will need new guides, hardened seats installed then a valve job. By the time your done you will be close to aluminum head price.
 
RustyRatRod said:
It will cost between 400-8-- bucks to have those heads properly repaired....possibly more. They aill need guides as well, I am sure. Guide and seat work is not cheap. Add up guides, seats, valves, springs, retainers and valve locks. Then the labor involved. It's going to get expensive pretty quickly.
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Gotcha, yeah sounds like finding another set of heads will be the way to go.

@George Jets I looked into those RockAuto heads some more, the ones that are in stock are the ones with holes for air injection. But l could just plug those holes, and all factory 360 heads are basically the same in terms of flow and such right? Especially for a bone-stock app like this.
 
MopaR&D said:
Gotcha, yeah sounds like finding another set of heads will be the way to go.

@George Jets I looked into those RockAuto heads some more, the ones that are in stock are the ones with holes for air injection. But l could just plug those holes, and all factory 360 heads are basically the same in terms of flow and such right? Especially for a bone-stock app like this.
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Yes can just tap some 1/4" threads and plug those smog holes with some 1/4" allen screws.

Here are a set of the later 596 heads that I rebuilt myself, new valves and guide seals.
All the 360 head castings are all the same flow and port size, just different casting numbers.

1011161505.jpg


The later 360 heads have the hardened seats so they don't sink the valves like your 915s did.
 
Excellent, I'm going to go ahead and place an order for those RockAuto "smog" heads then. Thanks for all the advice guys, this will save tons of time and at $582 total cost including shipping and core charge I'll probably still be saving a few hundred bucks over having my heads machined. FABO rules!! :thankyou:

Not to mention I'll have a spare set of J heads to mess around with in the future or sell if I feel like it.
 
smart move , good luck with the repairs , truck should run well with the new heads
 
George Jets said:
Yes can just tap some 1/4" threads and plug those smog holes with some 1/4" allen screws.

Here are a set of the later 596 heads that I rebuilt myself, new valves and guide seals.
All the 360 head castings are all the same flow and port size, just different casting numbers.

View attachment 1715563747

The later 360 heads have the hardened seats so they don't sink the valves like your 915s did.
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With the stock exhaust manifolds, you probably don't even have to plug the smog holes. They should cover them.
 
cudamark said:
With the stock exhaust manifolds, you probably don't even have to plug the smog holes. They should cover them.
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I do have long-tube headers I'm going to install, or actually was in the process of installing when I broke an exhaust stud lol.

I actually think I'm going to go a different way getting replacement heads, a member on here has a set of rebuilt 596 heads I should be able to get for a slightly lower price than the RockAuto remans but with stainless exhaust valves. I also just prefer to do business with a fellow FABO member as opposed to a big supplier when possible.
 
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