Moparts Tech Archive
Stage VI head questionsv8440
From: Montgomery, AL
Registered: Jun 2002
posted 06-30-2002 01:02 AM
I can help you with #3. Mopar makes a special valley tray for the Stage VI's. 4876847 for the B blocks
Also yopu use either a smallblock plug or hemi plug brand heat range personal choice the big block plugs do not have long enough reach
v8440, did you have to do any "extra" work to get the heads ready to use? Just concerned about all the negative feedback on MP Stage VI heads thats been going around.
Thanks for the answers, I had to get the deck surface milled on my heads because I bought them used. I also had to get a number of other things done, all related to the fact that they were used. So, to answer your question, I really don't know what things might have to be done with a new set. What negative things have you been hearing about the heads?
I run a set of those on my stroker I usually run autolite 64 or 65's. I would run a head bolt with a washer like ARP's other than that they are stock length on the bolts.You can fabricate your own Valley tray theres not much to them. I made my own with some aluminum hold down bars for the ends.
Porting results w/ MP Stage VI templates
No doubt that the best "bang for the buck" standard-port big-block Mopar head right now is the Edelbrock. However, some of us went w/ MP Stage VIs before the E heads were ever released (or even conceived). I don't know how many people are sitting on Stage VIs, or can get a set cheap enough to be worthwhile (they'd have to be pretty cheap, IMO), or already have them in some mildly modified form. Regardless, this information may be helpful to those of us who _aren't_ using Edelbrocks.
lift-------in / ex
This was actually the best of all four intake ports by almost 5 cfm. However, all the exhausts maxed out at 138-139 cfm (in other words, all were consistently bad!). Anyway, I got the bug up my butt to see how easy it was to get some reasonable #s out of one. I fiddled w/ one cylinder doing nothing but some bowl blending and minor profiling of the short-turns. There was w/ no work at all on those big-ass guide bosses:
lift-------in / ex
Obviously, the exhaust picked up way more than the intakes for such a minimal amount of work.
Then, using a combination of what I'd seen with the PRH heads and the MP templates to fall back on, I went back into the intake port to reduce the guide size (what a freakin' pain!), more blending in the bowl, and some additional work on the short turn. No work past the bowl area at all, so the rest of the port was as cast. This was still just a cuttered finish except some minor polishing of the short turn - and ended up with the following results:
I'm no pro porter, but I'm no hack either. IMO, this is close to what can be expected from somebody who does a careful job w/ the MP templates.
However, I compared the results to the PRH heads and noticed I wasn't seeing very big #s at .500-.600", although the .100-.400" #s were as good or better. This isn't necessarily a reflection of my porting, because the latest generation Stage VIs, of which my first set are, don't seem to have as good low-lift #s compared to the earlier castings.
With some minor additional profiling to the short turn, more trimming of the guide boss, smoothing the ridges & high spots left in the bowl from the previous work, hand-blending a steeper angle into the bowl from the 60-degree cut below the 45-degree valve seat, straightening out the cylinder-side wall where it merges into the bowl, and opening the pushrod pinch area to approx. 1.10+", I got another 5 cfm at .500"+, which wasn't much for the time I spent doing the work noted. I started experiencing the law of diminishing returns rather quickly.
At this point I was swapping e-mail w/ Dwayne Porter because, to be blunt, I thought I'd done a fairly decent job of copying much of what he'd done w/ my other heads and wasn't seeing as good results. For comparison, here is the average of all eight intakes for the PRH heads:
One of the key areas we discussed was the short turn. Me being me (i.e., always thinking of trying something different), I didn't copy Dwayne's short-turn profile. Instead, based on some stuff that Steve Dulcich had written and other heads I'd seen or read about, I put a more convex shape to the short turn, thinking this would help the flow at higher lifts w/ less turbulence I'd seen w/ my first heads. Well, maybe that wasn't the right thing to do w/ the Stage VI after all... I tried "fixing" the short turn based on what Dwayne told me worked well for him, opened up the width of the port at the short turn, plus increased the bowl area slightly on the long-turn side, all in my attempt to reduce the velocity into the bowl and help the air turn.
OK, obviously that was a waste... and the loss of 2-3 cfm between .400-.600" didn't exactly bring a smile to my face. Anyway, I'm probably done messing w/ this port and will try something different on the short turn w/ the next one.
Now, to be realistic, this isn't horrible for an under-210 cc port (forget what MP claims, these measured 193 cc w/o any porting, IIRC) and compares reasonably well to some other small-port heads. A "good" uported cylinder from 440/451 Jim's Edelbrocks (they seem to have "good" and "not as good" intake ports, from what I've heard) showed this on my flow bench:
An out-of-the-box (does anybody actually run one "out of the box"?) Indy SR w/ a 260+ cc port volume generated these results:
Also, we tested two Edelbrock ports Jim modified somewhat (no huge changes) and came up w/ these results. Since he did comparable mods to both, I think what you've got here is an example of those "good" and "not as good" ports I mentioned above...
lift----- #3 / #1
Oh, so what happened to the Stage VI exhaust port, you ask? Well, that port got treated to the MP template job, too, along w/ _minor_ additional work I did "just because". I didn't open the port size any, nor did I mess w/ the cast-in bias to the outside wall. Once again, this is probably typical of what Joe Average could do w/ the MP templates. I've listed results both with and w/o a 2" "flow tube" that Jim Hanrahan made me.
lift--- w/o / with
Once again, I've got out-of-the-box Edelbrock exhaust port results courtesy of Jim Hanrahan's heads:
lift--- w/o / with
However, compared to the PRH-ported exhaust ports, my MP-template job is pretty weak at high lifts. Here are w/ and w/o flow tube results:
lift--- w/o / with
Jim also came up w/ some really respectable exhaust port #s from his Edelbrocks based on porting guidelines Dwayne provided. Once again, these are w/ and w/o flow tube:
lift--- w/o / with
So, what was the point of all this? Crap, I figured somebody would ask...
First, I've learned that getting _big_ #s from these heads isn't as simple as DIY porting using the MP templates. However, the results from that level of work are still an improvement over the ported OEM '452' heads that put my junk into the 10s on pump gas. Here are flow #s from my old my old ‘452’ heads (average for two cylinders tested). Although not taken from the same bench as other flow #s shown here, I believe they're close enough for comparison:
lift-------in / ex
Here I've consolidated the results for the work I did while, basically, following the MP templates:
lift-------in / ex
Second, I'm not sure who I want to bitch-slap more... Edelbrock for not having released their big-block Mopar head six months earlier so I could have bought those instead of my Stage VIs, or MP for selling the Stage VI head in such rough form (and w/ a variety of quality control issues) that it takes significant extra work (and $) simply to equal the Edelbrock out of the box.
Third, may I suggest that any back-yard porter contemplating doing anything more than a basic bowl blend and gasket match to their heads think twice. Hell, I've got a flow bench of my own to test my work and still spent more time than I want to admit grinding on my heads for little or no results. If you don't have some pretty good directions to follow (like the articles Steve Dulcich wrote on porting MP Stage V and W-2 heads), you're just as likely to be making things worse as better.
Steve D. - I'm only down on the Stage VIs because they're way overpriced compared to the Edelbrocks, and they've had (especially the latest ones) some real quality control problems. The set PRH did for me needed new guides right out of the box, the valve heights were all over the place, the chamber volumes between the pair of heads (even after equalizing the valve heights) weren't even close, and the exhaust ports have a lot of core shift which results in "good" and "bad" ports. Also, even though MP talks up their "out of the box" valve job, the latest heads like those looked like the seat cutters were way past needing replacement. It cost almost as much to straighten out the MP QC issues as the porting did. My second set, which are a previous generation that still have the hughe valve guide bosses and were CNC-machined in the chambers, aren't nearly as bad as far as seat height variation or core shift. However, the chambers are so wide that they'll need to be milled about .100" simply to make them fit w/in the fire ring of a head gasket, I suspect the guides are (yet again) too loose, and one of the alignment dowel holes on each head isn't even drilled in the right location. If they sold 'em for $349 each bare, some of this would be easier to rationalize. But at $700+ each bare, it's tough to justify.
As far as port measurements, the way I did it was to start at the port entry and go in approx. 1" w/ each increment. The closest thing to a short-turn measurement was the height taken 3" in from the entry, and the width taken approx. 1.5" back from the centerline of the guide into the throat.
Entry - 2.16 H x 1.15 W = 2.48 sq in
I wish I had a digital camera to take pics of my work, because I figured you'd be interested in seeing how I did the short turn. The transition from the runner floor to the drop into the bowl seems pretty smooth to me. If anything, I may have carved away too much of the short side attempting the convex form (it's pretty freakin' laid back). The floor is lowered slightly starting just past the pinch point (as suggested by Dwayne), but I didn't take a huge amount out here. Previous velocity probing I did on the PRH heads surprised me because the floor, especially approaching the SS turn, was much more active than I'd expected. This made me wonder if, contrary to most people saying not to lower the floor and concentrate on the roof, these heads might respond to additional work there.
You're correct in that the MP valve job short-changes the benefit the large(r) valve because the seats aren't placed far enough out on the valve to take advantage of the valve's full potential. However, I'm working w/ the out-of-the-box valve job at this point.
Steve - If you've got any images of what you did to the MP head that you can e-mail me, please do. I'm interested in seeing the extent of the work. Also, I'd have contacted you directly about questions re: the convex short-turn form, but I suspect you guard your e-mail address like Fort Knox! LOL
Brad, excellent, excellent info. here. I think you're making a real valid point about the VI heads. They CAN work, but at this point unless you get them real cheap, or have them already, why??
Thanks for the info. Brad. The day will come when its all back together and the work you are doing now will pay off. Watch and see.
Your right, we didn't do before and after on #1. I did feel around more in all the runners to try and duplicate the small changes in #3. A pro would know how to get these over 300 cfm, but not me!
Bad Hemi - I don't have part #s in front of me, but can probably dig some of them up later. IIRC, there has been one part # for the "standard" Stage VI head since they were introduced, but that head has gone through a couple of changes in the last 10 years (first a foundry change the, later, changes to the guide bosses primarily). I have also seen part #s for unported assemblies, ported assemblies w/ 2.14" & 2.18" valves, CNC-ported assemblies, and bare heads w/ CNC-machined chambers, not to mention a couple variations on the Max Wedge version. I doubt I could find them all, between discontinued and/or superceded stuff.
I have a set that was made in '91. I bought them for a decent price in '92 (~1000$ complete) and portedthem. Don't have a flow bench, but our pump gas '451' made 649 hp in the dyno on pump gas with them. Last winter I wanted to add the port displacement and did that too. I raised the mouth of the port cosiderably, then going towards the valve I widened and slightly angled the floor ending up with 220cc ports. No flow bench results, but so far in the initial testing it seems that we have more power than previously. In the winter we should take the engine to dyno and see how it compares with the previous results.
i recently freshened up a set of stage VI's for a customer who originaly got them from MM.
i only tested one cylinder, as the work looked reasonably consistent from port to port, and i didnt feel any of the ports would have a huge difference in flow from another.
this is what i got as the heads came to me:
the intake flow was pretty much what i expected, but the exhaust flow was pretty weak.
the decision was made to go for some more flow, so i took that same cylinder and did the same basic work i did to Brads heads, however this is without putting the head on the guide and seat machine, and cutting the seats/bowls.
that work netted these results...same port as before.
i was very happy with the intake results, but i knew the exhaust numbers should be better still.
this is how it ended up:
the intake port openings were left the same size as the way i got them, in fact all the porting i did to the intake side was done from the pushrod pinch area inward.
and with the valve removed from the port completely, and just a stem in the guide to plug the leak the flow was 342.3.
it just so happens that while Brad was wrestling with his new stage VI test head, i was doing this set of heads. when his convex shape didnt appear to be working for him, i sent him these pics of what worked for me on the short turns of those heads.
in any case....im very anxious to hear how the car now runs with the extra flow.
Great info fellas, Brad/Dwayne, even though I am going to use the E heads it's still good to know you can do the same (if not better) with the 6's.
What are your guys' thoughts on the
I might imagine that the angle plug/heart shaped chamber would be the ultimate, but with these heads you can't have both at the same time!
Do the features cancel each other out to some extent?
PRH results: .600--310.1/233.8
That intake runner flows really nice now, the valve is the limitation.
Let's see, recent customer, MM stage 2 porting, I wonder whose heads those are? I've been happy with my stage VI's, although as Brad H said, with the choices out there today they would be pretty far down the list. I think when I bought mine your choices were Indy 440-1's, B1's, and the b1-bs had been released but I had little info on them so I passed (I still haven't actually seen anyone run those heads to this day). I saw a local racer running Stage VI's in a Dart that was running high nines on a fairly mild combo so I figured the potential was there for anything I wanted to do. It will be interesting to see what the car et/mph's at next time out.
"What are your guys' thoughts on the straight vs angle plug, and heart shaped vs max wedge shaped chambers?"
Re: chamber design, I think that's a little clearer. The old Max Wedge-type chamber doesn't appear to offer any significant improvement over stock in terms of swirl potential, vs. the modern heart-shaped chamber. The MW-type chamber also doesn't offer nearly the quench area that the old 915 iron head did. The chamber design was one of the few things about the Edelbrock heads that I was disappointed in, especially because their small-block Mopar heads use a modern chamber design.
This does even more justice for Fast's port work that 451's listing at .600
I guess if there was soap in the gas tank, then it would make more sense
The E heads do have an antiquated looking chamber, no doubt.
One thing that some of the small heart shaped chambers do better,IMO, is help steamline and direct the flow on the chamber side.
My biggest question on the MM porting was that when I purchased the heads and ordered the "stage II" porting I "assumed" that some kind of data sheet would be included. To my dismay there was nothing. I called MM and they pretty much beat around the bush, but I pretty much got the idea that I payed for an "eye ball" port job and from the exhaust numbers I must have only paid for porting on the intake side. Not much I could do from there. Thats why I was curious what the "as is" numbers were on my heads before I had Dwayne work them over for me. You'll have to look at it from the stand point of that this was also my first big block that a friend and I had ever put together, hell we didn't even know you had to notch the block to make the rods fit! (4.15 stroke) All in all I'd say we were lucky that the engine ran as long and as hard as it did. Best to date is a 10.70 @ 123. Next year? we'll see
Procharged...sorry...no pics of the exhaust.
just look at a stock BB head exhaust port from the header mounting surface inward(they also have a very biased exhaust port) to get an idea of what i mean.
Ok, After doing a little diggin, move parts washer, 2.2L crank, and toss the 10/10 440 crank outa the way, Presto! A BB head. Your right. Almost no gap what so ever between the valve guide boss and the inside wall. Basically none. Almost seems to be blocking that side of the valve totally from sight. Wonder how much meat is there? Thanks for the tip.
Just wondering what the velocity is like in them heads, port design & contour have an effect on what maximum velocity the air can go & still follow the contour.
It was a lot of reading but had that in mind when Brad mentioned something he did.
On the topic of angled plugs this is how I understand it, it moves the plug closer to the charge area & also the squish area, maximum turbulence is steered toward the plug to help combustion & pressure rise, good for using higher compression.
It is an interesting topic. Like maybe Edelbrock should try an buy Mp out of the heads and making them into a Victor. Seems they overpriced and under quality and that Edelbrock could make them the next move up if we could get those numbers out of the box and mp already has some for bigger valves too. Can you say gone in nine seconds. The 440-1 might have to sweat it if a set of them were in the next lane. I like the Mp head trick of using 440 intakes on b blocks and the Spacers for the big block. It would give the 440 manifold's a longer shot and we could run any manifold we wanted on em.
That brings up another detail I was always curious about. How does that adapter affect head flow? I used to run the adapters with my M1 open plenum 4150 carb set up. I switched to the newer "stage vi" intake for a 4500 series carb. By the way swapping the 850 and intake/spacer combo, to the 1050 carb and intake dropped my et nearly four tenths and picked up four mph. It was after this little experiment that I really wondered if my heads could use more flow. My engine obviously reacted well to the increased air flow.
Fast One - I did some velocity tests w/ the heads that PRH did for me. If I can dig up the results, I'll see if they make any sense to post. BTW, I didn't do any air speed calc's, just mapping of manometer readings at different locations in one intake port.
"JBODY - When Dwayne did my heads w/ the adapters, he straightened out the roof so as to eliminate the dip (although the drop in the floor at the junction is still there)."
I did wonder about the velocity because some port designs tend not to follow the contour if air speed gets over 350 feet/second, mapping the port flow velocity & graphing it's performance in the valve area would be quite interesting but also very time consuming, flow bench research can be quite addictive & I'm not surprised your car isn't finished yet ( ha, ha )
Here's the port mapping exercise that I did on one of the PRH-modified heads. First, I mapped the intake port as six sections:
At port entry:
1" into port entry:
2" into port entry:
3" into port entry (essentially right above short turn):
very interesting....im actually suprised the pushrod side of the port is the "busy" side for most of the way through the runner.
your mapping does show how the air is sliding towards the bore center, which is what i thought was happening, i just didnt think that side was busier than the other side of the port at the short turn.
I looked at those results and had to double-check that they were for #3 and not #1. I'd also done some tests w/ a couple of intakes attached using manifold runners #3 or #6, so it was definitely #3 tested. "Truth is stranger than fiction..."
Is that an example of the "venturi effect" in action ? Where the port narrows for the pushrod, the air is picking up velocity as it travels over/around this, right ?
Normally one would think that the air column would be getting squeezed to the outside wall and then possibly crossover at the short turn crossing the back of the valve.
Well that is certainly interesting, especially 2 inches into the port & the lower left if I read that correctly.
Taking the extra out of the roof seemed to ease off the traffic jam of air around the short turn showing more valve for the air.
I've found that my best improvements for mid range cfm is in the pushrod side of the runner wall & upper cfm the roof.
The opposite side of the runner I do some work there but not too much.
I always give the guide area a good workout.
I'm very careful with the short turn, a little bit of work then onto the flow bench, a little bit of work then onto the flow bench again & so forth...
Bad Hemi asked about part #s for Stage VIs. I found '96, '99 and '02 MP catalogs and
Fast One - I agree raising the roof would help for the same reasons you mentioned. However, if you're not familiar w/ the Stage VI, one of the limitations is how high you can raise the roof because the raised port itself runs right under the spring seat near the base of the guide. Unfortunately, there's not much meat to carve on before seeing daylight from what I can tell. If the roof's height-limited and the floor's "busy", looks like lowering the floor may be one of the few ways to add much volume to reduce the velocity there. That's something I'm interested in trying, but haven't really taken much out so far (and didn't see anything worth noting for what I did).
Also, the PRH ports didn't appear to "find" any more CFM when tested at 28" than at 10", given the difference between my bench and a local SF-600's results were only about 5 cfm. That little change could be attributed to normal variation between benches, not the test pressure difference.
Yes I'd forgotten about the roof limitations in the big block heads, most of my experimental is with small block.
(weld the the roof some & raise it)
Anyway I'll put this picture in to show what I do in the production small block runner wall, I start with the pinch slightly because it's not very thick there & gradually take more as it gets closer to the bowl area, the picture is approximate but just gives a little bit of an idea.
This type of grinding does seem to really wake up the mid range where the cam lobe spends a great deal of it's time.
As you know the flow bench is only a tool but a useful one even though other factors can't show on the flow bench like, air density, thermal transfer from the engine to incoming charge, mass of fuel, piston design, stroke / rod ratio, piston speed, engine rpm, intake manifold tuning, blah, blah, blah...
..and like I said earlier my hogged out Stage VI's have 220 cc intakes, they were about 190cc untouched.
Nice pic Fast One.
On the earlier heads the pushrod wall side usually is quite generous in thickness, up to 6 mm or .234 in
Brief update. Based on the feedback I'd received on the intake port, I went back into it and carved on it some more. I have to admit that I broke the first rule of testing and did a bunch of minor(?) changes at once because of time constraints. That said, what was done included...
This seemed a step in the right direction (at least for offsetting what I may have done wrong).
The exhaust port got the following:
Exhaust w/o tube
Exhaust with tube
Looks like this was a step backwards everywhere but .600+". Oh, well...
its funny how certain people have a knack for certain types of ports.
on the other hand, i really struggle to get the big numbers out of Indy SR's. its all in the sort turn on those(for me anyway).
by comparison, i can remove all the material i need to on an older stage VI buide boss in waaaay less time than i have in an SR short turn, and up to this point anyway, ive had a really easy time of it with regard to the stage VI intake short turns.
Ha, yeah been down that road before, did the usual porting thinking this will be good & it ends up not doing what it should in theory.
As for the exhaust, hmm, minor loss in the lower lift, opening the width of the runner might improve that but maybe you shouldn't tempt fate, your heads though.
I found some figures from a set of 915J heads I did, probably the best I got so far without welding, I'll include some figures from a welded exhaust, both figures are with 1.60 SpeedPro nail head exhaust stainless.
Unwelded 915J maximum porting.
Welded 915J exhaust
Notice that there's no great improvement between .200 - .400 lift, how ever the air traffic has moved up higher with good results.
But now here's some results with just swapping over to Tulip valve in the exhaust, no extra porting & same head
Interesting eh!, just swapping the valve design made good changes all through the lift range.