Latest 440 Source Stealth head set

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IQ52

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We were asked to do a pair of the standard 440 Source Stealth heads, good to .750" lift, for a 451 stroker in Iowa. When we first spoke he wanted 600 HP with a turbo charger. He has since revised his attempt to 750 HP normally aspirated on pump gas. The latest standard Stealth offerings from 440 Source come better bowl prepped and have better OOTB flows than we have seen previously. This is what we shipped a week ago.

Lift.............OOTB................ported

.100...........73/60.................80/67
.200.........151/122..............157/139
.300.........214/165..............220/190
.400.........245/196..............269/228
.500.........262/218..............306/255
.600.........276/220..............334/275
.700.........281/236..............345/287
.750..................................345/293
 
Thanks IQ, I think we all appreciate your willingness to post this kind of information.

IQ52 said:
The latest standard Stealth offerings from 440 Source come better bowl prepped and have better OOTB flows than we have seen previously.
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I'm actually about to buy a pair of these so I'm interested to hear about any improvements in quality. In the past I've read that Stealth heads will need at least a valve job before being ready to bolt on and go. How did these ones look? Are they more capable of being a ready to run head?

Thanks!
 
I really appreciate the great service I get from 440 Source. I wish the heads were something I could say, "Just bolt 'em on." I cannot. It should be noted that I would NEVER bolt on ANY factory assembled head, OOTB, from ANY manufacturer, not Edelbrock, Indy, Brodix, Dart, RHS, 440 Source, NONE OF THEM.

Now back to the Stealth head.

I highly recommend that you use 1.5:1 ratio rocker arms on the Stealth head. Get a cam lobe that will give you the lift you want! 3/8 pushrods and 1.6:1 ratio rocker arms require extensive grinding to clear the intake port. The 1.5 rocker will give about .050" more room right from the get-go. You CAN USE the 3/8 and 1.6:1 combination and still get 345-350 cfm. We do it, but it is a balancing act.

For the most part, you could replace any Mopar factory iron head with an OOTB Stealth head and it would work just fine for a long time. I DO NOT recommend doing so.

The quality of retainer has improved in that you get a more uniform spring installed height. The older retainers would sometimes be .020" different.

I have found, very often, the valve stems are scored just below the locking groove. This seems to be caused by dragging the locks with retainer as the head is assembled. I replace (or repair if possible) 4-6 valves on each set of heads.

The locks still cut into the locking groove at the tip end, and if not filed prior to removal, will cut into the bronze guide. So I still say to replace the retainers and locks even though the box says they are using some Comp Cams parts.

The bronze guides are about .040" larger in outside diameter than the standard .502" guide. Therefore one could buy a bare head and ream the guides to 3/8, using a supply of on hand 3/8 stem valves, should they choose to do so.

The OOTB valve job will generally seal and be better than a stock head but still leaves much to be desired. I find that a few of the guides will be a little tighter than I like, though none have ever been too loose.

The valve spring pressures have been as uniform as and equal to the Edelbrock RPM head.

I haven't had any problems with casting flaws like porosity. The machined head surface is generally flat enough to seal with a composition head gasket, but we find that just clean cutting them always reveals some slight twist or warp.
 
thanx for sharing the results on the steath. I may stop by your shop this summer, if your around when i'm in the area. i have some interest in getting a set of these prepped heads and maybe a stroker in the near future.
 
That's everything I need to know and then some. I feel like a thief getting this kind of information for free :thumbrig:
 
fishmens67 said:
thanx for sharing the results on the steath. I may stop by your shop this summer, if your around when i'm in the area. i have some interest in getting a set of these prepped heads and maybe a stroker in the near future.
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Stop on by, we love visitors.
 
IQ, so if I read this correctly, you assert the stealth heads aren't bad as far as aftermarket pieces go but to get the most out of them or even consistency, it's likely better to buy them bare and have a machinist go through them with a fine tooth comb and install good parts from the get go.

I have a pair of 516s that have already been ground/cut on and an untouched pair of 915s for my 383...but I don't want to rule out the possibility of running aluminum heads, and I know regardless of which direction I go, I'm likely to spend at least $1k just in machine work and pieces parts to go into whatever castings I have...the only significant difference being if I take those 915s anywhere, the labor cost will be more for any port work due to time involved, but I would like to achieve 400rwhp out of an N/A 383...
 
What kind of tricks do you use to boost the low lift numbers of a big block head, if someone wanted a set like that? I think personally I would want good velocity and really healthy numbers in the .200 - .400 range, rather than a peak high lift number...would that require welding on the floor and some re-contouring of the port?
 
I have a set of the first stealth heads when they were released.Still in the box never opened.I've heard about the retainer problem and will replace them and now check for damage to the valve stems before installation.Thanks for that info.I also have a set of 1.6 rockers and the 3/8 push rods.All of this has been sitting on the shelf for about 6 years now.Glad you posted this thread.Thanks again !Procrastination payed off.
 
txstang84 said:
IQ, so if I read this correctly, you assert the stealth heads aren't bad as far as aftermarket pieces go but to get the most out of them or even consistency, it's likely better to buy them bare and have a machinist go through them with a fine tooth comb and install good parts from the get go.


I have a pair of 516s that have already been ground/cut on and an untouched pair of 915s for my 383...but I don't want to rule out the possibility of running aluminum heads, and I know regardless of which direction I go, I'm likely to spend at least $1k just in machine work and pieces parts to go into whatever castings I have...the only significant difference being if I take those 915s anywhere, the labor cost will be more for any port work due to time involved, but I would like to achieve 400rwhp out of an N/A 383...
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On the Stealth, depending on how you want to go with them would determine how complete you buy them. All out, maybe bare. For a general build with some extra power, get them complete.

400 RWHP is a bunch outta a 383, nearly 1.4 HP/CI at the flywheel. Can be done, but I wouldn't skimp on the cylinder heads then. Any iron head will have to have some real work done to them. On a 915 you will need valves, guides and port work to the tune of about $900 to get to the 265 cfm range, roughly the flow of an OOTB Stealth. Then there would be the added cost of retainers, locks and springs depending upon the cam. I don't believe that would be enough to get to the 400 RWHP goal. The 915 can be taken over 300 cfm but then it does get expensive.
 
451Cuda said:
What kind of tricks do you use to boost the low lift numbers of a big block head, if someone wanted a set like that? I think personally I would want good velocity and really healthy numbers in the .200 - .400 range, rather than a peak high lift number...would that require welding on the floor and some re-contouring of the port?
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I appreciate the honesty of the question. Please kindly accept my honest reply.

We've worked long and hard to discover that information. It is now how I earn my living. I get paid to supply THOSE answers.
 
IQ52 said:
We've worked long and hard to discover that information. It is now how I earn my living. I get paid to supply THOSE answers.
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AKA; As in not tell you but port your head for you.

Ya can't ask him to give away be secrets! A good magician will not tell you how to make an rabbit disappear. Same for the head porter. It would be insane to knowingly commit financial suicide.
 
But yet you guys do it every day. Not only with head porting but with whole engine setups. I dont mind helping out and I do it A LOT, for free. Then when I do spend hours upon hours on the phone, emails back and forth and someone wants to order a part and I get " Hell I can get it $XX cheaper of this guy on ebay, Sorry pal", that burns my ***. Pump me for all the info then pull it out right from under me. It happens all the time, but Im still here. Theres a reason why Indy is the way they are. You dont want to give them a lot of money for their time, they have no time for you. I choose to NOT be like that and just shake my head and wait for the next call or email.

Then there is the other end. I have had a few guys on here just send me $$$ for helping out, $20 or $30, but hell thats HUGE in my book. Didnt ask for it, but they felt the info provided was worth something.

Rant over ;)
 
451Cuda said:
I got the answer I was after, and I wasn't expecting him to divulge any details of his methods.
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I know, and I believe that Mike does too, that the very request for information, is in a way, a sign of respect for our knowledge. We sometimes just mention that there is a boundry and hope that in doing so, we are not offensive.
 
You guys,are here to make a living,doing what you love.MRL's post,priceless. Worked for an engine builder.Wouldn't return phone calls,for "1200 dollar,budget builds". 600,to 1000,just to properly square up a 30 to 40 year old block. Thanks,for your time,guys.
 
Abodybomber said:
You guys,are here to make a living,doing what you love.MRL's post,priceless. Worked for an engine builder.Wouldn't return phone calls,for "1200 dollar,budget builds". 600,to 1000,just to properly square up a 30 to 40 year old block. Thanks,for your time,guys.
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Money hungry hippos. I'm a young person that builds 1200-1500 dollar motors. I stay out of machine shops here in Oklahoma simply because unless you're spending 10k+ you're a no body.
 
600HP doing a 451 with a Turbo Charger is crazy, more like 1200hp. You can get 600hp out of a 318 with a Turbo!:burnout:
 
Mad Dart said:
600HP doing a 451 with a Turbo Charger is crazy, more like 1200hp. You can get 600hp out of a 318 with a Turbo!:burnout:
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Of course you are correct.

The point we were making at the beginning was that he was seriously under estimating what his engine would be capable of.

I've never run any boost, never needed it to accomplish my goals. I was at a dyno contest when the chassis dyno owner/operator pulled me over and asked if I was interested in putting on a turbo or ProCharger. He said, "Jim, if you let me throw some boost to your engine (a 451 with 906 iron heads that was making 554 RWHP), I can get you 1500 RWHP.

He had previously put boost on cars making less rear wheel horsepower than we were at the time and they were making 1100-1400 rear wheel horsepower.

The gentleman we did the Stealth heads for, is now aware that he has cylinder heads that are now capable of blowing the crankshaft right out of the bottom of his block, if he throws boost at it.
 
IQ52 said:
Of course you are correct.

The point we were making at the beginning was that he was seriously under estimating what his engine would be capable of.

I've never run any boost, never needed it to accomplish my goals. I was at a dyno contest when the chassis dyno owner/operator pulled me over and asked if I was interested in putting on a turbo or ProCharger. He said, "Jim, if you let me throw some boost to your engine (a 451 with 906 iron heads that was making 554 RWHP), I can get you 1500 RWHP.

He had previously put boost on cars making less rear wheel horsepower than we were at the time and they were making 1100-1400 rear wheel horsepower.

The gentleman we did the Stealth heads for, is now aware that he has cylinder heads that are now capable of blowing the crankshaft right out of the bottom of his block, if he throws boost at it.
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I hear ya. There is a guy on theturboforums.com that is doing exactly that and his compression is up there too like in the 10.5:1 range. It is a Big Block Mopar pushing well over 1500rwhp with a Huge single turbo and Meth Injection.
 
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