440 source heads

Anyone tried the stealth or super stealth heads from 440 Source ?

What kind of power can be made with those ?

Dan

I have them on my street strip 440. No problems with them. Changed the springs/locks/retainers over to Comp Cams products. Had to enlarge pushrod holes for pushrods,2 shops checked them over and found no problem with them at all.Standard Stealth heads.

had stock Stealths , were great . Now have CNC version - even better

Tex

I have the super stealths, they take .650 special offset intake rocker, they need a LOT of work to make them flow 330ish CFM @ .700 lift, my car runs good, but there are much better heads out there, if I was to do it over I would get the Trick Flow 240 for my application. My car is not a max effort build, it is a street strip car, so far with traction problems, no tuning yet, 12.03 @ 116 MPH 1/4 spinning, 4100 lb with 3000 ft DA , 512 low deck small solid FT cam, .576 ,248 @ .050 9.5-1 comp.

Did a low compression 440 with Stealths replacing 452's. Fun little ride until I grenaded the 440.

Took those heads, sent them off to Modern Cylinder Head for CNC port, and slipped them on a 505" stroker shortblock.

They did have new (not Source) locks and retainers installed by a local machine shop when I bought them.

Very mild hydraulic Howards roller and 3.54 gears.

Best of 11.19 @ 121mph with 60 ft. still needing work in 3,600 lbs. with driver.

4,000 street miles and tons of dragstrip passes in last two seasons.

Flow 267 on my bench out of the box and go 300cfm easily with some loving care.

Miles away from the Edelbrock
stuff !!

do the Edelbrock flow what they claim ? my Super Stealth out of the box flowed the same as the stealth OTB, 267,on my bench, same as Pittsburghracer's #'s

I have a 4.150 stroke 440 block stroker motor with a set of 440 Source CNC ported heads in my shop now that broke a exhaust valve guide bottom off and drop some of the debris into the combustion chamber NOT GOOD
The same customer had another different bracket motor that he broke a exhaust valve off a new set of the non ported 440 Source heads in the water box doing a uncontrolled burn out so keep that in mind
There are some people who can screw up a 5 ton wrecking ball in a sand box with no tools, other than themselves

I bought a set back in 08'. I upgraded to 10 degree keepers and ran them for a few years than changed the springs and had some port work done on them. There are a decent head for the price if your looking to save weight, but if it is a race head I'd consider Trick Flows as they seem to be a better bang for the buck.

After living through 3 cracked Stealth heads within 2 years (one lasted 3 or so passes), a fabbed oil pan that didn't fit, or a fabbed timing chain cover that was 1/8" off, I avoid them for pretty much everything. You get what you pay for...better quality options out there for a lil more coin. Pay now or pay later.

Only benefit I can see using their Stealth head is they somewhat resemble a stock iron head when they're painted, at a quick glance.

Stealths have basically the same POTENTIAL as Edelbrock Performer RPM, since they are the same ports & chamber wrapped in an OEM-style casting. It comes down to what level of work is done to them.

Stealths are a step-up stock replacement head. As said above, they have the same potential as the RPM head. A basically stock but prepped Stealth head on a mild 440 can make 510-520 HP. A very well ported (very expensive!) Stealth set of heads can make 750 HP. If you intend to race, buy another head.

For $89 more..... I'd just get some E Street heads.

In fact...... That's exactly what I did.

For me, the Stealth head is a budget head for those who really want/need the straight plugs, and/or the OE type appearance.

Between the RPM/Stealth/Sidewinder heads, I find the Stealth has the weakest exhaust port....... And the Sidewinder is the easiest to get to 300cfm on the intake side(IMO, it has the best short turn of the 3).

The RPM/E street is American made(a plus to me), and has quite a bit more room around the intake pushrods, so 3/8" pushrods and 1.5 rockers usually fit without any clearancing.

Ok Thanks
Dan

Is the MP 452 head still out there? Like an Edelbrock RPM with straight plugs?

Stealth head porting results from flow tech today.

Is the the super stealth version?

Uhhhh... whomever owns that flow bench needs to get a set of PTS calibration plates (http://www.flowbenchtech.com/orificeplates.html) and/or some stiffer springs to keep the valves at the specified height when flowing heads. Those low-lift #s are in the Twilight Zone.

I know flow bench #s can't be compared DIRECTLY, but when they're using a common calibration standard you can expect they're going to be REASONABLY close.

Larry Smith's posted #s:

.100" - 120
.200" - 177
.300" - 239
...

MCH's CNC Stealth program advertised #:

.100" - 75.0
.200" - 156.7
.300" - 219.8
...

The high-lift #s might be perfectly comparable. However, when I see that the low-lift #s are so far off from "normal", I feel the need say something 'cuz it brings the credibility of the whole flow test into question.

Don't shoot the messenger! It is what it is...

Kinda why if I don't see before and after numbers I keep moving on. Same bench before and after and you compare to what you see on your bench. It takes me less than 5 minutes to check intake and exhaust calibration and I do so before every different head goes on my bench. And I'm not even selling anything, I just want to know for myself. LOL

The calculated flow for the curtain area of a 2.14 valve, .100 lift @ 100% c/d(like flowing a straight tube)is right about 100cfm.

Typical c/d at low lifts is 60-80%.

that said, it seems the flow #'s from the facebook pic grab could start at .200" lift...

or bench could need calibration, really no telling without more info..

Here are the full curve comparisons...

Larry Smith's posted #s assuming the lowest #s are .100":

.100" - 120
.200" - 177
.300" - 239
.400" - 282
.500" - 312
.600" - 324

Or, assuming the lowest #s are .200" (which I don't believe to be the situation):

.200" - 120
.300" - 177
.400" - 239
.500" - 282
.600" - 312
.700" - 324


MCH's CNC Stealth program advertised #:

.100" - 75.0
.200" - 156.7
.300" - 219.8
.400" - 266.2
.500" - 298.8
.600" - 314.9
.700" - 320.7


I can't add anything more to this topic, and still question the bench calibration or some other condition that's resulting in unrealistic low-lift #s.

Regardless, carry on with your bad self!

My total guess is...... There's a leak, causing the big low lift numbers.

the only reason to have Stealth heads is for the stock look. if you should ever damage a Stealth head & it requires welding, you might as well throw it in the bin & buy a new one. They're cast from a low grade aluminium that does not respond well to welding. I have repaired a set of Stealths that needed welding but the cost was more than a new head. go figure.

This is what I got out of my Super Stealths on my bench
OOTB
.200 140
.300 202
.400 242
.500 256
.600 267
.700 267
after
.200 157
.300 217
.400 264
.500 290
.600 314
.700 335
.800 345

Which way?

Mine have been on since they came out.They get beat on pretty good.I did change springs,retainers, and keepers because i run a 588 solid cam and 4 speed.My machinist did some clean up and like the look.He was a perfectionist.Happy with them and i needed straight plugs for my dome pistons.Rocky

Ask him on his fb page.

Case in point....... I flowed one of the MCH CNC ported stealths about 5 years ago.....

.100---72
.200--159
.300--220
.400--266
.500--293
.600--309
.700--313

The thing that's almost never mentioned, and would have more of an impact on the higher lift flow, especially as the flow numbers get bigger......is the shape of the radius for the air inlet.
This can result in a 1-3% difference in flow(or more if its a particularly bad one) on the same head, on the same bench.