Performance Heads For 440

[BANGSHIFT440]

BUILDING A 440....ARE THERE OPTIONS OUT THERE AS TO HEADS????ALUMINUM SOUND GREAT BUT ARE THERE ANY CAST HEADS THAT ARE GOOD BUT NOT SO$$$$$$$$$$

[6 packin]

Late model heads work great! 452 are just as good as the older ones. The have harden exhaust seats for unleaded fuel! But remember that any machine cutting on the seat will cut the hard surface treating away! I personally dont belive in the hard and soft seat deal. I have run the soft seat heads for years and years. with no failures! I personal run 516 closed chaber heads with big 2.14 intakes and 1.88 exhausts, with major port work done. Take a late model seat of 452's and do as much bowl porting as possiable! They will support at least 500-600 horsepower~!

[rumblefish360]

The Edel.'s ported out a bit from Indy I think? or Hughes is a good deal.
The cost is about the same to a bit cheaper than iron heads. Worth every penny. Start a savings piggy bank now.

[DartGT66]

the E-brocks are good even oput of the box from your nearest dealer. In Edelbrocks, there is not much to be achieved with porting, maybe 10% with a pretty big work. On my opinion, not cost worthy for the gain.

[KM]

Just use the e-brocks and be done with it.

Kimmo

[Doug Wilson]

I have stock 452s on my 440/452 tow engine. If I were to think about porting, I'd spend the money on Edelbrocks, rather than having someone else port my iron heads. I can't do my own port grinding. Also, with the Ed. heads, you can run (at least) 1 more point of compression, and they also save you 40 pounds on the front end.

If money was no object, I'd buy the Indy modified Ed. heads, for about $2100.

Also, to 6packin - the hardened valve seats are not surface hardened.. they use a much harder steel - maybe Stellite? - and are hard all the way through. Grinding them for a valve job does not change the degree of hardness in hardened valve seats.

[jlcoffell]

If we are voting I would go with the aluminum Edelbrocks.

I have just recently gone through a head job. I searched through
wrecking yards looking for the newer 452 casting heads or the
older 906 casting heads. I was never able to find a pair of 452's,
found 1, but did come across a set of 906's. After the machine work was done, hardened seats installed, stainless valves etc.
Using mostly Mopar Performance parts, with the original purchase price of the heads at $165.00 for the pair, I have a total of about $1000.00 into them.
The Edelbrocks are about $1300. Save yourself the extra work and spend the additional 300.

[6 packin]

I was told buy a old local mopar guru/machinest that mopar Nitride treated many things and it is however just a surface hardening tech! Just like the old hemi cranks. There are no seat inserts like the ones you purchase for old heads its the same metal. I somewhat am spectical on the soft seat and hardseat issue. I cant ever remeber anyones heads failing due to this??? I know for a fact I have a set of 906 that has been run for over 15 years and 150,000 miles plus with no trouble. But doest mean any else will have that luck. Most of the time the valve guides are the big issue with mopar heads due to side loads. And when running bigger cams maes it alot worse.!

[Doug Wilson]

My factory stock 452s have hardened inserts. Maybe someone else had them installed, but I think they are factory - Anyone?

You're right - guides and stem seals are long term issues with any of the MOPAR heads.

[jlcoffell]

Since I just finished working through this issue I still have some
of the details fresh in my head.
I was told by an old Mopar Mechanic that the 452 heads already had the hardened exhaust seats installed as they are the later
model heads.
The 452's are supposed to outflow the 906's at higher rpm's. They don't flow quite as well at lower rpm's. (this is per a previous question you might look it up in the archives).
Thats why I was looking for 452's first then 906's as the 906's do not have the hardened exhaust seats installed.
Now I am no professional but I was told by the machine shop that did the machining that the older heads will run quite some time on unleaded before showing any problems. They claim the exhaust seat area can become so hot that it starts to soften. The exhaust valve will then actually sink into the metal slightly which they called "Valve Recession". If you have a hydraulic cam/lifters etc. you won't notice a problem for some time.
When I pulled apart my engine with 516 casting heads it sure looked as though I had 3 exhaust valves that were in the head farther than the others. Valve recession ?? Does this really exist ?
I have not measured the installed height as I already had the 906's ready to go on so it was really a don't care.

[Doug Wilson]

I think I read that the 906s and 452s flow the same, the differences are: hardened valve seats on 452s and combustion chamber ccs.

[dave571]

jlcoffell

Valve recession really exists, and you've seen it.

Thats the result of running unleaded fuel in early(non hardened heads.

As for the hardening issue, I was under the impression that in later heads, the seats were "flame" hardened. What that means exactly, I don't know.

There is a really good chart of head flow rates(67 and later) at www.moparmusclemagazine.com Click on the rotating header at the top of the page, when the title "cylinderheads pt 1" comes up.

[Doug Wilson]

Dave - This is a GREAT article, and anyone with any interest in big blocks should consider it a "must read"!!! It went into my archive.

It also made me completely reconsider my approach to the build of the 440/452 tow engine. Thanks a lot!! - engine is mostly done, and now I have to replace my 452s with the ones from my '67 Imperial, and either deck the block to zero deck height or get new pistons. Also, thanks to you, I have to do some new/different valves, and some exhaust porting.

Thank you VERY much.

[gsmopar]

Holy smokes! If that chart is correct I can't wait to fire up my new EB heads!!!

Yet another thread that reinforced my EB purchase.

Later,

Greg

[6 packin]

The sinking of valves is going to happen regardless of seats hard or soft! Just think about the pounding going on! But what hurts the most is regrinds, continous valve jobs will sink the valve quicker than most anything! Because your machining part of the seat itself! There is no head made that will resist. Unless you never fire it up! If you can actaully see the valve sinked in the head with the naked eye there trash! The easiest way for your average joe to see, is too put a straight edge over the valve tips! Im thinking .020 is alot! This however can be simpliy fixed buy going to a bigger valve! There is no accurate way of looking at the heads and seeing just how much is there???? Just use a straight edge and some filler gauges! Just some info Id thought id share.

Bob


Bob

[deadhorse66]

Originally posted by Doug Wilson
I think I read that the 906s and 452s flow the same, the differences are: hardened valve seats on 452s and combustion chamber ccs.

Here's how most manufacturers did hardened exhaust seats on iron heads: Cast the head, send it through the mill (everything is made of cast iron), and use a process called induction hardening to get the hardened exhaust seat. This consists of sending an electrical charge through the seat area, causing the iron to heat up, burning some of the impurities out and making the iron around the seat area more dense and more hard. It is similar to turning the iron into steel, but not quite as strong. Since this hardening was only approx. .002" thick, it would wear away with mileage, and is removed when any machining is done to the seat area. The lead in fuel acted as a cushion and a lubricant, so hardened seats were not needed up until the early '70s when fuel started to go to low lead, and eventually no lead. Running an unhardened seat on unleaded fuel will actually flatten out the pores in cast iron causing the head of the valve to "sink" into the head. Once you have the valve out of an unhardened seat head, this will be quite visible, especially after 150,000 miles. The seat will no longer have that sharp 45* angle where the valve actually seals, it will be more of a rounded ditch which will sink into the 30* angle on the chamber side of it. This will not cause any drivability problems other than leaking valves which results in decreased effective compression and a loss of performance. Keep in mind that it takes quite a bit of running time for this to occur. The only instance that I can think of where seat inserts are installed from the factory is on an aluminum head, and this includes both intake and exhaust seats. Doug, 452s and 906s are supposed to have the same chamber cc, and the 906s have a steeper short turn radius which is supposed to equate to more flow at high lifts. The closest thing I can think of to a 452 is a 346, just going by chamber design, valve size and short turn radius.

[Doug Wilson]

Thank you for the info, y'all!

[deadhorse66]

I just read the Mopar Muscle article, and it said about the same thing I just did. (deadhorse beats on forehead and repeats: stupid! stupid! stupid!...)

[Doug Wilson]

I did, and thank you for your effort, anyway.

[ajmopar]

Valve seat recession definately occurs! I had a set of J heads on my 360 that I ran for about 15,000 miles and pulled them to find the exhaust valves sunk about 1/16" in to the head. I had stellite seat put in and a good valve job done and all was hunky dory. I pulled the 452 heads off my 400 with about 120,000 miles on it and the exhaust valves were pitted but the seats were fine with a mild cleanup.
BTW weren't the seats induction hardened on mopars? That's where an electric coil that fits the seat is cranked up until it heats the seat area orange and then cooled to harden it.

[jlcoffell]

This might be slightly off this topic but I am curious as to what exactly is open chamber, closed chamber etc.
The 906 casting being the open chamber version with the older
516 castings being closed. The difference I can see between the heads is the combustion chamber. The 516's have the recessed area around the valves only, with the 906's having a circular recessed area that somewhat matches the cyclinder bore.
I use the 516 and 906 castings for reference as that is what I have. Is this what differentiates open vs closed chamber ? I don't exactly remember for sure but when I was searching wrecking yards for heads and found 1 452 casting head and I recall it looked like the 516 casting where the recess was only around the valves. Isn't this considered an open chamber head ?
Also do you not loose compression by switching from the 2 different designs? I ask about the compression as I originally had 516 heads installed and have now switched to the 906's.
How much compression did I loose. I have 11.1 to 1 pistons so I am hoping for maybe a 1 point loss Hopefully!.

[hotrod7043]

all your engines from Mopar 72 and up had hardened seats from fact thats when the nolead fuel came in.

[Doug Wilson]

You are right about the differences between open and closed chambers. The 452s are open chambers. I know that this will maybe cause some discussion, but open chamber heads supposedly flow better at higher RPM, because there is less shrouding of the valves. Closed chamber heads have higher compression, using equivalent pistons. To achieve the same CR in an open chamber, you need to either install pop-up (or domed pistons), oor mill them a bunch. Of course, if you mill them, you go right back to shrouding the valves.

You should lose AT LEAST one compression point with your swap. To be sure, you should cc the combustion chambers on each, and compare them.

[dave571]

If you want to know exactly what compression changes you will have, use the compression calculator at www.kb-silvolite.com.

click on calculators and input your info.

You'll need to know alot of specs(how far up the piston comes ect)
Typically the closed heads are about 78 cc and the open 88 or 90.

Doug is probably right about the full point thing, if your up as high as 11:1 to begin with. You'll find the change to a stock 400, by switching open and closed heads is minimal. Alot more visable on a 440.

Be careful though, your 11:1 pistons probably come up above the block deck, and may not be able to be used with closed heads(they'll hit). Some pistons are made to be used in this situation(shaped so they only come above the deck where the open valve area is.

Doug, no problem on the aricle. It is really interesting, isn't it? One of the better articles I've ever read in a Mopar mag.

Good reading for everyone here, that's for sure.

[Doug Wilson]

Amen!

[charger_dan]

I'd score a set of the E-brock heads, run them out of the box for now, then have Dave Hughes port them when I had the dough. From what I've read here, they're a great value.

[Doug Wilson]

Yup.

[DartGT66]

11:1 pistons, with what head cc? I ask this, because there used to be a lot of different CR pistons available that were announced to be 11:1 with for example 73cc chambers; there are no such heads. Typically factory BB open chamber heads have a chamber at around 90cc and closed chamber heads at around 80cc. Milling the open chambers about .040" will bring them equal to the closed chambers as far as the chamber size goes. Flow and performance wise they are better than the closed chamber heads except the '915' heads which are the same basic port design as the newer heads. How much CR you'll loose with the additional 10cc's depends of your current CR and the engine displacement.

[hotrod7043]

so rt DArt iwas on the phone just the other day for specs on a set of srps i bought like 3 yrs ago he give me ratios for84 cc , 80, and 72cc which he refer to as the small chamber head i have a set of 915 have ben millled the previous owner told me and they are at over80 cc wish the piston mfgs would get it together.

[DartGT66]

The first thing with these things is to measure everything and not assume anything.