There is a set of rebuilt big block heads near me that I am thinking about putting on my 440. the casting # is 3462346. The motor I have is an 77 motorhome engine that is going into a 66 Sport Fury. The guy wants $350 for the heads and they look nice. They have been milled .020. What do you think of these heads and do I have to do anything special to the intake manifold because they have been milled.
Thanks

they are garden variety iron open chambered heads. Not sure if they would have hardened seats but I dont think so. What was done to the guides? If you get em mock them up on the block with a couple of head bolts per side lightly snugged with your choice of head gaskets to hold em in position & set the manifold down on a new valley pan to get an idea of how much milling is needed & it'd be better to mill the intake face on the heads rather than the intake itself which if you do that (milling the intake) then the intake only fits that combo. between the milling & the gasket thickness & the deck height which could be anywhere you need to mockup & see where you're at & go from there & if the block decks are straight you could use steel shim gaskets with aluminum spray paint as you need all the compression you can get (which wont be much). Talk to Hughes about a cam. EDIT If you are going with an iron OE intake it might be appropriate to install/torque the heads then mockup the intake & mill the intake instead since it ain't likely you'd be swapping an iron intake to another eng somewhere on down the line but it would be recommended to check flatness on the heads' intake surface & the intake as warped surfaces are the cats' ass & very common & vac leaks are a real pain to diagnose/fix

They aren't really any better than the heads you are removing from the engine , the plus is they are easy to get gains out from porting. The heads you have removed had flame hardened exhaust seats those won't. Make sure you use the correct springs your cam choice requires.

You really shouldn't have any issues with your intake, the intake side of that head SHOULD have had .024 milled off it. But if it hasn't it is said that you won't see any real issues.

Use a steel shim headgasket , put a coating of coat gasket spray on it , both sides. If you use a composite gasket any tiny gain of compression from the head being cut, it really isn't much , will be lost.

thanks for the help the heads have the hardened seats and bronze valve guide liners. The reason I am thinking about changing are the motorhome heads are unique one year only and take different sparkplugs than the normal big block heads.

Don't waste your money.

First of all, what is the casting number of your existing heads?

Second, have you tried to buy a 3/8" reach gasketed plug at your local WalMart lately? It's harder to buy such a plug than it is to buy one of the plugs I am assuming your heads use. The 3/8" reach tapered seat plug was used on millions of smallblock chevies, among others, and are everywhere.

Third, the ports and combustion chambers on your existing heads are the same as the 346s. Same low-flowing ports, same horrible combustion chamber.

Fourth, you are 1/3 of the way to a set of Stealth heads from 440Source, which will make a real difference in how the engine runs.

Fifth, 0.020 is nothing. So if you DO decide to buy the heads, using a composition 0.040" gasket will have the head exactly where it would be if it had not been milled and you used the stock steel shim gasket.

R.

Sounds like I am going to stay with the heads I have, thanks guys!

346 heads are 71 383 and 72 400. Not sure if they are 440 also for 71 and 72.

346 heads were found on all B/RB engines. We're not in chevy land here!
R.