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... but if Mopar guys dont abandon the misinformation about valvetrain geometry, they will never be able to compete at the same level as the competition.

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Please to elaborate, honorable B3RE-san.

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Sorry if this was covered, What rockers did you use for this build, and how much work was required to get them working with the head mods? Also would you expect the same/worse/better results with victors?

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I used T&D shaft rockers in a 1.6/1.6 ratio. The only work required was milling the shaft stand down .030" with a 7/8" ball endmill.

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This is why you had instability. How many finalists had valvetrain issues with their hydraulic lifters? I'm sure they didn't just put the roller in the center of the valve and call it good. Not trying to be a jerk, I'd like to see you do well, but if Mopar guys dont abandon the misinformation about valvetrain geometry, they will never be able to compete at the same level as the competition.i
Kudos ony all the hard work on the cylinder heads, though. I like to see people thinking outside the box.

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How would you address the geometry issues with Mopar's shaft system. I am all ears. Short of milling the rocker stands down and moving the shaft in 2 of the 3 axis, I do not see how it can be done. Please enlighten me so I can understand. J.Rob

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More questions:
1. Was the engine in the same state of tune when it made 720-ish HP on your dyno as when it cranked out 750+ HP at the EMC?

2. Why the major "fat" dip in the A/F ratio down low? My first thought was that big-venturi "True 950" Holley wasn't happy under a load down there, but would have expected it to be lean, not uber-rich...

3. Do the flow #s you posted reflect the head being positioned in an "adjusted" location over the bore fixture comparable to where it was on the engine w/ the offset dowels, etc.?

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More questions:
1. Was the engine in the same state of tune when it made 720-ish HP on your dyno as when it cranked out 750+ HP at the EMC?

2. Why the major "fat" dip in the A/F ratio down low? My first thought was that big-venturi "True 950" Holley wasn't happy under a load down there, but would have expected it to be lean, not uber-rich...

3. Do the flow #s you posted reflect the head being positioned in an "adjusted" location over the bore fixture comparable to where it was on the engine w/ the offset dowels, etc.?

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1. The engine was fattened up 3 jet sizes at EMC to adjust for the oxygenated VP100 fuel that I was unable to test with prior. I also added 2 degrees timing for a total of 38. This helped midrange torque and the average quite a bit. I did leave home with the tuneup with a little left not wanting to chance a last minute failure and missing the EMC altogether. That story is all too common. Once down there though I am willing to get aggressive with the tune-up in the search for points. I would have fattened it further and made a high speed bleed change if time had permitted.

2. The fat dip down low is almost always IME due to reversion/cam overlap just before it gets to its happy place. It was far worse before we added 18" collector length. We shortened them 2" and lost all of our gain. When we cut those off to extend them back we though if long was better then lets put 20" .Our collectors were about 2 inches too long. This engine was really cool in that it had 2 very distinct surges in it power band. I have video and you can watch the torque needle surge and level off then surge upwards again. You can try and make it leaner in that range but power will suffer just below it or above it or both.

3. Yes, My flow fixture-plate is doweled and the flow chart is exactly how they were flowed. Only thing I neglected to mention was the bore fixture was 4.375" diameter. In fact I think I may put 4.375" flat tops-which will put this somewhere around 14-1 and 470 cubes and see if 800 hp is not achievable. J.Rob

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That`s the fuel I run in my 470 also. Any other issues or tricks to gettin the most out of it? I`m at 12.1.1 comp. w/72 cc`s and rpm heads............thankxx 4 the info..........

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Short of milling the rocker stands down and moving the shaft in 2 of the 3 axis, I do not see how it can be done. Please enlighten me so I can understand. J.Rob

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Looks like what you do is use offset rocker stand spacers to more closely approximate Jim Miller's Mid-Lift Geometry design. Of course, his design applies to both the roller-tip fulcrum sweep as well as the angularity of the pushrod-to-rocker relationship.

Simply offseting & raising the shaft can only help to improve the roller tip sweep, unless you happen to be working w/ rockers where the angle of the pushrod adjustment screw is less than optimum when in the standard location. Some rockers do respond positively to that, but with others (Crane "Gold" being a good example) it just makes the adjuster screw angle at peak lift even more out of parallel w/ the pushrod than before.

I always found it interesting that Miller's approach and Jesel's were so very different, considering Jesel takes what they refer to as a "low pivot" approach to minimize rocker scrub in the high lifts where the spring loads are greatest, despite the overall scrub pattern being wider.

I'm curious how one uses offset rocker stand spacers w/o redrilling (offsetting) the bolt hole (which ICH did in the Mopar Muscle Engine Challenge entry w/ the T&D rockers mounted on spacers). Does this involve elongating the rocker shaft mounting holes to enable shifting the shaft c/l rearward? I think I've seen some Harland Sharp SBM shafts like this.

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Points well taken BradH, but a allow me to make my case.

First, while Miller's approach does address both the valve and pushrod side of the rocker, you are at the mercy of the manufacturer you choose when buying rocker arms. That adjuster angle is near impossible to correct once designed into the rocker and machined accordingly. But, having the valve side of the equation correct is far more important and beneficial to the performance and longevity of the valvetrain. Plus, having the valve side correct will allow for less spring pressure and not having to use "special lifters" that are unheard of in the world of the competition (chevy, ford etc.). I'm not saying the pushrod side isn't important, but it doesn't compare to the valve side. BTW, I have a set of SB Crane Gold's, circa 1998, on the bench right now that I checked the adjuster angle on a CMM and they were only out by 2 degrees. I've had them off by ten degrees or more.

Jesels low pivot approach is a mystery to me if not completely counter-intuitive. That low approach means the valve opens more slowly than it would with Miller's advice, and accelerates as it gets closer to full lift. I don't know about you, but my cylinder heads always flow more air at .500-.600 lift than they do at .200-.300 so I want to get it there as quickly as possible (think "fast cam lobes"). Then the valve does not decelerate as it should at full lift and now the valve becomes very difficult to control (more spring). At best, you may gain a few thousandths at full lift from the reduced sweep on that end, but you have given up way more than that all the way from the seat up to that point due to the slower acceleration down low. To me, the spring loads would be greater doing it Jesel's way just because of the need for more open pressure. Then, on the way down, the rocker moves quickly from full lift and slows once it gets to the lower lifts (harder for the valve to "keep up" and less time for the port to flow good air). From a purely logical standpoint, it doesn't sound like a good thing to me.

In most cases, I do not need to elongate the holes in an aftermarket shaft. There is usually enough wiggle room to get the offset as long as the rockers aren't commercialized. By commercialized I mean designed with a longer fulcrum length to put the roller on the center of the valve when just bolted on, so people will buy it on the premise that it has better geometry. I'm sure one brand in particular comes to mind. The shafts you speak of are made by Comp as well and they are marketed as offset shafts for more spring clearance. Funny, I don't have spring clearance issues when the shafts are raised to the proper location. Not saying I never will, just haven't so far. BTW, have you ever priced those shafts? Oh, and you would still have to offset the stands somehow.

One question, what do you consider optimum adjuster angle?

Thanks for the thought provoking conversation. I like it.

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This is interesting. Not a Mopar but shaft rocker.
http://www.flowspeed.com/titan-rockers.htm

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Thanks for bringing this subject up as I am building a max wedge engine and the heads have no rocker stands. I will be getting billet stands made and I knew there had to be a way of figuring the optimum height.

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