Whats the Deal on Stealth Heads

[jyrki]

Today, I measured certain things and took the heads apart.  I won't go in to greater details, but for example the valvestem heights were very colse. The assembled heights varied , noticably in a couple of cases, but mainly my measurements showed pretty even 115 lbs seat pressure The highest was 120, and the lowest 110, so actually very good. open pressure at .5" lift was about 290 with 1.9" installed height.The port opening locations were very good, but the chamber locations seemed to vary. The width of bridges between the chambers can be seen visually.
http://kuvablogi.com/nayta/906919/
The other head was the same, so apparently they came from the same mold. Didn't measure the chambers, bu will after they ahve been made about the same according to the cylinder bore locations. The seats hang slightly in the ports at some points, and the bowls overall are pretty large, perhaps even a bit too large?
Didn't check the deck straightness either, or the valve job. The guides weren't too tight. The valve locks are rediculous even compared to the factory ones, and in my opinion shouldnät be used in performance heads. I would change thes to machined ones in my set.
However, in my opinion the pair I had would most likely work just fine out of the box, if the chamber/gasket overhang will not give any troubles. I don't know if it will; I had a used 8519 set, and it felt like it had hung over the chamber too at similar points, but had not leaked. I don't recall which heads these were used with, but these gaskets with stock polished "452" chambers were far from the gasket edges. I also tested the MP Stage VI porting templates. It's pretty evident, that at least these aren't Stage VI copies.     
ui'll give these a big thumbs up so far, after the minor problems are solved.

[Draginmopars]

NOWWWWWwwww, That's why I came over to THIS site,,tell it like it is and NO BS ,About  ........  Thanks for checking out the heads, what you said is what I also see with mine. Due to the  , I will give mine, I'm using 10*locks-Comp 613-16 and 10*retainers-Comp 747-16
The slight lip under, the seat insert, I'm gonna blend it as best i Can.I have access to a full machine shop.. I checked my heads on a Surface plate, head sitting on the deck, A feeler gage(.002) would not go under, anywhere end to end. All the Valve tips, were with-in .001 in height also end to end.  The other things you have already mentioned..

I know, it's to early, I Would like a head, Just to CUT-IT-UP,, to see what can be done to them..   I'm in the middle of STUDYING, This head,from the conbustion chamber (Ihave tried, I just can't get a GOOD/ no reflection pic, And I'm NOT gonna scuff, the wall just for a photo.   according to my "braille" meter, they Feel pretty good.

[R5-P7 project]

Hi Guys, just got my stealth heads welded. Well, I mean the pushrod groove that is
cut into the port wall; well, it isn't anymore. I also welded the top of the intake ports
inside the valvecover area so the ports can be raised. Next, the valve guides come out
and 7mm ones go in for the intake and 5/16 for the exhausts. This simple modification
will enable the porter to bring these ports out to maxwedge size. You have to be
careful at the top of the port under the spring seat, there's not a lot of meat there.
I wish I could of bought these heads completely bare; sure would have saved me a lot
of time. I'll try to get some pictures posted soon.  Cheers,  Budd

[Draginmopars]

Hi Guys, just got my stealth heads welded. Well, I mean the pushrod groove that is
cut into the port wall; well, it isn't anymore. I also welded the top of the intake ports
inside the valvecover area so the ports can be raised. Next, the valve guides come out
and 7mm ones go in for the intake and 5/16 for the exhausts. This simple modification
will enable the porter to bring these ports out to maxwedge size. You have to be
careful at the top of the port under the spring seat, there's not a lot of meat there.
I wish I could of bought these heads completely bare; sure would have saved me a lot
of time. I'll try to get some pictures posted soon.  Cheers,  Budd

   thats the info I'm looking for, What  off-set intake Rocker arm will you use? , and like you, I feel the Push rod pinch area needs to go..For MY Application.. Felpro 1218 Max Wedge,                  Exhaust - Mr. Gasket #7167

[jbarker]

Hey jyrki-
Thanks for reporting with all the good info.  You always have something useful to add.  We appreciate it.
-Jay

[slippery440]

I too came over from the other site and have found alot of good info.We are going to just touch up the seat area and the push rod pinch.How much do I dare to take off that push rod pinch without going thur?We will be backcutting the intake valve for alittle more flow.Plus we are taking the exhaust port out to the copper gasket size.My machine shop likes the heads so far.

[Draginmopars]

 Welcome, I've only been here 2 days, like it here, 
IF, <I don't find the off-set rocker I want..
Then I'm going to open the pinch, until It is .100" thick.> between the port wall and push rod hole.
This is ONLY MY, thoughts, I can be wrong,might go thinner,(.060 ) it is what i'm going to try.
It will only be thinnest at a small vertical area.,the port is thinnest>Near the top, of the wall
This is a Track only engine. 

[slippery440]

Mine also.Just a bracket car.I forgot to say tha we are going to take .080 off the deck or what ever that gets us down to a 76 cc chamber.

[dusterdood]

Hey vic, these didn't have any of the problems with the head gasket over hang, right?

[Draginmopars]

Mine also.Just a bracket car.I forgot to say tha we are going to take .080 off the deck or what ever that gets us down to a 76 cc chamber.

 I haven't got that far, I was, just fixin to go to the shop, I'm working on the exhaust ports> before and after volume.
porting,using the cooper seal gasket/template.
 I always do the exhaust first. You can only put in, What you can get Out...N/A
 
 of course, Let >US< know , how much, cut it takes for 76cc.
I don't know, where my Comp will be yet, until I can do a V-to-P check.

[slippery440]

Hey vic, these didn't have any of the problems with the head gasket over hang, right?

I order Rol head gasket from Mad Dog Racing and they are not here yet.The ones that I ordered say they are .039 compressed but have the same number as the .045 gasket. I will get back to you. Right now making a choice to try to make up to the machine shop or let this darn snow  that is blowing at mock speed win out. I hate winter.

[thecarfarmer]

Bumpin' this thread for some tech ???s...  Been thinking of buying bare castings and having 'em finished... first, have to take care of a huge dent in the side of Mrs. Carfarmer's car.  She-who-must-be-obeyed is not going to be happy if I put moving forward with the pickup ahead of taking care of that!  But I guess that gives me time to formulate a game plan, and only buy things one time...

How big a deal is it to run a 4.500" diameter gasket on a 4.28" bore?  The difference is .220; but that means that the recess on one side of the cylinder or the other is going to be .110".  I understand that any little nooks or crannies where unburned fuel mix can stagnate isn't a good thing, but how much loss of power are we talking about on the typical 550-650 HP application?

Also, it was recommended that these heads might benefit from a larger valve, like a 2.19".  Who are good suppliers of oversize valves with small stems?

Thanks to everyone who's taken the time to share their experiences.

-bill

[Draginmopars]

Bumpin' this thread for some tech ???s...  Been thinking of buying bare castings and having 'em finished... first, have to take care of a huge dent in the side of Mrs. Carfarmer's car.  She-who-must-be-obeyed is not going to be happy if I put moving forward with the pickup ahead of taking care of that!  But I guess that gives me time to formulate a game plan, and only buy things one time...

How big a deal is it to run a 4.500" diameter gasket on a 4.28" bore?  The difference is .220; but that means that the recess on one side of the cylinder or the other is going to be .110".  I understand that any little nooks or crannies where unburned fuel mix can stagnate isn't a good thing, but how much loss of power are we talking about on the typical 550-650 HP application?

Also, it was recommended that these heads might benefit from a larger valve, like a 2.19".  Who are good suppliers of oversize valves with small stems?

Thanks to everyone who's taken the time to share their experiences.

-bill

Bradon said " The next run of heads,
 "will be improved>
 no lip under the seat insert
 and a slightly smaller combustion chamber
 to adress the over hang issue.

[jyrki]

How big a deal is it to run a 4.500" diameter gasket on a 4.28" bore?  The difference is .220; but that means that the recess on one side of the cylinder or the other is going to be .110".  I understand that any little nooks or crannies where unburned fuel mix can stagnate isn't a good thing, but how much loss of power are we talking about on the typical 550-650 HP application?

It would not be a big deal at all. However, it will not help much either, since at the point where the problem is, the 4.59 bore gasket isn't any bigger. If brandon will take care of that in the next batch, then there shouldn't be any problem.

[myrtle]

DraginMopars: Got any more pics of your port/gasket maych job,..
I have thought about doing this for some time now and would just like to see some progressive pictures as well as what to expect with a final product.

Thanks

[R5-P7 project]

Hey Friends,  I've been trying to post pictures of my weld job, but for some reason I
can't get them posted. I'm a computer idiot, that's the problem. Maybe I'll figure it out
one of these days. It really turned out good. I also changed my guides to 7mm for
intakes and 5/16 for exhaust. You would be surprised how much weight that takes out
of the valve train. Well, if I figure it out; I'll post some pictures.  Cheers,  Budd

[ksdartguy]

You have to have pics smaller than 80kb to post.
Might have to shrink them a bit.
Rick

[Draginmopars]

DraginMopars: Got any more pics of your port/gasket maych job,..
I have thought about doing this for some time now and would just like to see some progressive pictures as well as what to expect with a final product.

Thanks

 Look at "Stealth" pinch wall thickness?   Post> I went "Hog" wild, diggin for answers.
got the exhaust roughed in last night and wait-in  to polish
 did some work on the intakes.

[therocks]

Im from the other site also.Cant get very much info there.Ive got mine at the shop for Comp springs 10 degree retainer and locks.My machinist ordered a felPro marine gasket in 4.50 bore to see if it clears the chamber.Does anyone have a set up and running yet?:Id like to know if they had a problem.Also what torque are you using.My ARPs say 60 ft lb with the lube.Seems a little light to me.Im going to start with Autolite 3924 plugs.I have 12.5 domes in the 440.Rocky

[ksdartguy]

I went 65ft/lb. with arp bolts and lube. Just about to get motor back in car.
A couple weeks and I should know something. I will post when I do.
I used 8519 felpros and drilled the dowel holes to let them drop about 1/16th.
Also cleaned  up ports a little and used comp 919 springs and 10% keepers to add .050 installed height.
1.950 installed at about 200# on seat for my roller. 
I feel good about the heads. Just need some time to get real world experience.
Rick

[therocks]

I believe I got the Comp 925 dual sprimgs with the Comp 748 retainers and 613 locks.Machine shop called Friday but was closed when I got the message.Ill talk to him Monday.Just hope the plugs arent too hot with my compression and MSD.Rocky

[slippery440]

I just got done doing basicly the same as Draginmopars. We cc the chamber and came up with 85 cc.We took .075 off and reckecked the cc and found 71cc.Would one of you guys recheck the compression ratio for me?
440 BORED OVER .030
ZERO DECK
FLAT TOP PISTONS WITH VALVE RELIEFE We cc them and they were 6 cc  Piston is out .001
ROL head gasket  They say .039 but the gasket is .045 before compressed so we called it .042? What would you guys use for that?
71 CC head chamber
2.14 INTAKE AND 1.81 EXHAUST
We came up with 12.26 compression

[fasttcars]

I just got done doing basicly the same as Draginmopars. We cc the chamber and came up with 85 cc.We took .075 off and reckecked the cc and found 71cc.Would one of you guys recheck the compression ratio for me?
440 BORED OVER .030
ZERO DECK
FLAT TOP PISTONS WITH VALVE RELIEFE We cc them and they were 6 cc  Piston is out .001
ROL head gasket  They say .039 but the gasket is .045 before compressed so we called it .042? What would you guys use for that?
71 CC head chamber
2.14 INTAKE AND 1.81 EXHAUST
We came up with 12.26 compression

normally the gasket will compress to the min 0.039 thickness    what was the gasket bore diameter?...i went with 4.440...and my claculation came out to 11.82:1  compression

[ksdartguy]

I ran it on Bowling and Grippos, and Hardcore Mustangs calculators.
11.5 and 11.37 is what I get. Hardcore lets you put in a gasket diameter.

Rick

[fasttcars]

I ran it on Bowling and Grippos, and Hardcore Mustangs calculators.
11.5 and 11.37 is what I get. Hardcore lets you put in a gasket diameter.

Rick

i think you made the mistake of putting the piston below deck  which is layed out with a + number   and everthing above deck  would be a - number cuz i redid the calculation and it  is still 11.82:1..but puting the piston below deck  it dropped to 11:22

[slippery440]

Thanks guys.I thought we cut a bunch off these heads.If you had to see the alum. shavings it was alot. I may take a wee bit more off to get 12.5. We did the calculations and kind of scratched  our heads thinking we did something wrong. 

[ksdartguy]

I ran it on Bowling and Grippos, and Hardcore Mustangs calculators.
11.5 and 11.37 is what I get. Hardcore lets you put in a gasket diameter.

Rick

i think you made the mistake of putting the piston below deck  which is layed out with a + number   and everthing above deck  would be a - number cuz i redid the calculation and it  is still 11.82:1..but puting the piston below deck  it dropped to 11:22

I used 0 deck and 6cc for the piston. I think the diff is in the gasket bore.

[fasttcars]

I ran it on Bowling and Grippos, and Hardcore Mustangs calculators.
11.5 and 11.37 is what I get. Hardcore lets you put in a gasket diameter.

Rick

i think you made the mistake of putting the piston below deck  which is layed out with a + number   and everthing above deck  would be a - number cuz i redid the calculation and it  is still 11.82:1..but puting the piston below deck  it dropped to 11:22

I used 0 deck and 6cc for the piston. I think the diff is in the gasket bore.

ok the zero deck will acount for a bit  cuz he also mentioned they were  out of the hole 0.001...what gasket bore did you end up using

[slippery440]

I used the ROL gasket and the one that was suppose to be .039 commpressed. 

[ksdartguy]

I used the ROL gasket and the one that was suppose to be .039 commpressed. 

I ran it on Bowling and Grippos, and Hardcore Mustangs calculators.
11.5 and 11.37 is what I get. Hardcore lets you put in a gasket diameter.

Rick

i think you made the mistake of putting the piston below deck  which is layed out with a + number   and everthing above deck  would be a - number cuz i redid the calculation and it  is still 11.82:1..but puting the piston below deck  it dropped to 11:22

I used 0 deck and 6cc for the piston. I think the diff is in the gasket bore.

ok the zero deck will acount for a bit  cuz he also mentioned they were  out of the hole 0.001...what gasket bore did you end up using

I used 4.41 gasket bore. I think we are close though. and .042 gasket thickness. and .001 shouldnt make
a whole lot, maybe a little.

Have to shave some more to get over 12 to 1.
Rick