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Rusty 049 Heads

3K views 29 replies 14 participants last post by  cv67 
#1 ·
I recently came across a set of rusty 049 big block heads. It looks like they have been setting on something wet for a long time and the surface is pitted. My plan is to have them cleaned, checked for cracks, and surfaced before I go any further with them. I'm hoping they'll clean up at .015" to .020".


The question is how far can these be surfaced before they are considered junk? What say ye?



 
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#2 ·
Wow, those look pretty bad. I guess if it were me I would look for another set.
 
#6 ·
I'd pay to have them steel shot abraided and make up my mind when I saw exactly what I had to work with. Pitting on the deck visible in the pic will be gone if you flat mill 'em to get compression up. If you're going to put big valves in them anyway, the current condition of the seats means nothing. They look pretty rusty but I've raised worse from the dead.
 
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#8 ·
Lots of decent BBC heads still out there for sale. Guy at our last of the year swap meet in the next swap space from me sold a set of 781's, great shape for $75. I did not think of asking because I figured he wanted $400 or more. Last time I make that mistake, from now on I will always ask.
 
#9 ·
Look at that picture close and you'll see one side is more rusty than the other.The spark plug/exhaust side of those heads are in much worse shape than the other,intake side of the head that doesn't look too bad.Run them by your machine shop before you invest too much $$ in them though.
 
#10 ·
The picture shows the worst of it. The other head isn't nearly as bad. In the picture I shined a flashlight across the surface to highlight the damage. The lighting makes the pitting look deeper than it is. The deepest pit I measured was .012". I know some guys have milled their heads considerably more than this to raise the compression ratio. I have also read milling these heads hurts the airflow. I know the pitting looks bad in the picture, but putting that aside, how much milling would you consider unacceptable on a big block head? I'm looking for a number.


I'd like to save these heads if possible, but I don't want to waste any money on junk. My plan is to take the heads to a local machine shop and have the worst one milled to find out what it will take to remove the pitting.
 
#12 ·
I'd just take it to the machine shop and let them tell you. if the valve seats shot, your going to have to go up in size. jim
 
#14 ·
I dont think that is the situation with these because there is no corrosion around the end water passages. I would bet they had been sitting out on the ground somewhere for 40 years :( I have seen afew like this over the years and they just are not worth messing with in my opinion.
 
#16 ·
If you'll be passing through northern Texas any time soon, I have a pair of rust free 781's I'll give you.

The more I look at those, the worse they look. Kinda like with my ex-wife toward the end of my marriage. I kicked her to the curb, I think you should do the same with these heads. And as was the case with me, you'll be money ahead and have peace of mind.

Can I get an "AMEN"???
 
#18 ·
While looking through some old posts on milling big block heads I came across this:
BTW,, flat milling rarely causes any [intake manifold] fitment issues unless it is quite a bit
I typically cut .015-.020 off almost every BB block I do & most heads are cut from the nominal 119-121 to 114-115 which is in the area of .040" & I do not have issues
This is the information I was looking for. The seats aren't sunk or pitted and the guides are in remarkably good shape. The only real damage I can see is the pitting on the surface. Milling heads is fairly inexpensive and if these heads will clean up with a .030" cut or less, and there is no other hidden damage, I will have them rebuilt. If they need more than a .030" cut to clean them up I will toss them in the trash.
 
#20 ·
Easiest way to get that rust off is with muriatic (hydrochloric) acid. You can spray them but it's a lot better to let them soak. A shallow plastic storage container from Wally World will let you soak one side of one at a time. It'll dang sure get the rust off and you'll know once you hose the deck of the worst one off whether it's worth it or not.

I diluted my acid with water. Add the acid to water, not vice versa. A gallon or two of acid will be plenty to clean both heads and it'll be pretty weak when it's finished. Wear good rubber gloves.

Just saw that you're in CA...so it'll cost you more than the heads are worth to dispose of the acid, so forget it...
 
#21 ·
I haven't taken these heads to the machine shop yet but I did sand blast the head pictured in the original post. Using a cheapo Harbor Freight dial indicator the deepest pit I measured was .012" deep. Most of the pitting is <.005". Being as these heads are almost 50 years old and getting hard to find I'm hoping these heads will be salvageable. It looks to me that this was a nice set of virgin heads that were not stored properly and left to rust.









 
#25 ·
:thumbsup: Didn't want to mention it earlier because the majority were piling on but I'm actually working on a similar looking set of BBC heads, mine are closed chambered, though. You and I think a lot alike on this. From your pics the throats and guides look good to me. I think the deck surface will clean up nice, at the worst there may be a few pits. Should seal without a problem. What's your sandblast set-up?
 
#22 ·
Yes that is a great decision you've made there.Throwing them away or scrapping them would have been a waste.Those 049's are one of the best, if not the best head made by Chevy in the 70's. And a good portion of that pitting in the ports will get ground away if you send them out for porting OR you can just clean them up yourself with a home porting kit.
For the record, when I store any cylinder heads I use a piece of plywood under them so they aren't sitting on wavy or damp concrete.
(I know you didn't let them rust, I just wanted to get that tip out there.Sometimes you can pick up small scrap pieces of plywood free at a local home being built)
 
#23 ·
Great looking port alignment on the intake gasket with no porting. Take .020 off the deck and see what they look like. If the seats are too far gone just put 2.19 and 1.88's in them, presto new seat with no pits.
 
#24 ·
Harbor Freight sells a porting kit & stones that's not bad for not much $ just don't over rev the arbor because they'll break and go flying across the garage BTDT :surprise:, I'd do that before sending them to the machine shop so you don't accidently mess any of their work up :thumbsup:
 
#30 ·
Id be afraid of corrosion from the backside of the bowl. I couldnt get more than 100+pair for some 290s...and square ports, the real popular ones? Look around as said or better yet your machinist. Many shops have plenty of cores laying around that are known to be good.
blasting brings back memories, did mine also. Removing the undercoating first took forever!! Sure looks nice in red oxide.
 
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