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Re: Chapman Stage VI 260 questions
[Re: Brian Hafliger]
#241977
03/03/09 03:07 PM
03/03/09 03:07 PM
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Joined: Jan 2003
Posts: 9,876
Weddington, N.C.
Streetwize
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Can't answer about the rocker offest, if a low deck roller probably so, RB flat tappet probably not.
installed spring height is standard but they use a longer valve (I used 5.350 standard BBC intake), Chap specs a 5.400 but the 5.35 worked great. As a result of the longer valves there's no 'oil pool' plunge cut spring seat pockets like the standard VI's. Better (much larger) roof to bowl transition too.
Intake bolts are the same as the Indy -1 kit (2 longer bolts between the intake ports)
Hope it helps, Brad!
Last edited by Streetwize; 03/03/09 03:11 PM.
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Re: Chapman Stage VI 260 questions
[Re: Streetwize]
#241978
03/03/09 03:54 PM
03/03/09 03:54 PM
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Joined: Jan 2003
Posts: 16,928
NC
440Jim
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Quote:
Intake bolts are the same as the Indy -1 kit (2 longer bolts between the intake ports)
Are all the Stage VI heads using those bolt kits? Or are the previous Stage VI use standard length head bolts? I will have to put a tape measure to the ones I used (ARP) when I bought the heads from the Engine Masters 470 competition. If so, Brad's existing Stage VI head bolts should work with the Chapman Stage VI heads. I am thinking those heads used standard Mopar BB head bolts? I forget.
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Re: Chapman Stage VI 260 questions
[Re: AndyF]
#241980
03/03/09 05:15 PM
03/03/09 05:15 PM
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Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
BradH
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Taking time off to work on my car
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For comparison...  My Stage VIs (updated to reflect actual results) Intake Port Volume: 215cc w/o RB spacers attached Chamber Volume: 78cc Intake Exhaust .100 67 56 .200 142 104 .300 204 148 .400 252 185 .500 287 214 .600 307 234 .700 310 246 Porter Racing Heads test of Chapman 260 Intake Port Volume: 260cc Chamber Volume: 77cc lift---in/ex .100--71 / 58 .200-150 / 119 .300-219 / 180 .400-279 / 219 .500-324 / 234 .600-352 / 243 .700-348 / 250 Current cam nets approx. .590" lift w/ 1.5s and I have 1.6s as an option in standard-offset rockers. I'll have to call Chapman for more information. It wouldn't be a cheap swap. However, I'm looking to run some 6.50 Index (1/8th) and 10.50 Index (1/4) stuff this year and the car won't be able to run close to either of those indexes once the summer heat & humidity sets in.
Last edited by BradH; 03/04/09 07:45 PM.
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Re: Chapman Stage VI 260 questions
[Re: AndyF]
#241985
03/03/09 06:18 PM
03/03/09 06:18 PM
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Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
BradH
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Quote:
Not sure how much it will pick up in the car with a full exhaust system.
That's pretty much what Dwayne Porter and I were debating when I called him on Saturday to ask "What if...?" re: Chapman heads.
Unfortunately, it's really one of those "Try it and find out" situations. It might not be as big an improvement as the increased CFMs would lead you to expect. Or... it could freakin' scream. 
According to Mike Lane @ Chapman:
- Chapman can sell them bare, w/ valves, or assembled as desired
- 1.950" installed spring height w/ "nothing special" hardware & their valves
- Use T&D rockers w/ .750" intake offset (I wasn't expecting that much was required)
- Use standard big-block head bolts (for 260s only?)
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Re: Chapman Stage VI 260 questions
[Re: BradH]
#241988
03/04/09 01:28 PM
03/04/09 01:28 PM
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Joined: Jan 2003
Posts: 75,043
U.S.S.A.
JohnRR
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Quote:
Can anyone here answer these questions re: the Chapman 260cc Stage VI heads? I'm trying to determine the real cost of upgrading to them from my current Stage VIs.
1. Standard installed spring height:
2. Intake rocker offset required (i.e. non-standard?):
3. Do they require longer-than-standard head bolts? If so, do the required lengths match the bolt kit for any other head available today (e.g. Indy or E Victor or...)?
Thanks,
Brad
Brad , I don't remember the spring height , but then again I sold mine bare , BUT the your current head stud set will work EXCEPT you need 4 studs that are maybe a .5" LONGER ( the ones that come up the middle of the siamesed intake ports) , I was able to get them directly thru summit with a std ARP number .
edit ... Didn't realize they needed the offset intake rockers , makes sense though , allows you to go to maxwedge window and one less machining operation for Chapman ????
Last edited by Johnahah; 03/04/09 01:33 PM.
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Re: Chapman Stage VI 260 questions
[Re: 70VcodeCoronetRT]
#241989
03/04/09 03:36 PM
03/04/09 03:36 PM
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Joined: Oct 2003
Posts: 3,698
NE Oklahoma
Von
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NE Oklahoma
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Quote:
Hey BradH just curious, what are they selling them for bare?
2600 bare, 2800 w/valves, 3200 complete
72 RR, Pump gas 440, 452s, 3800 lbs, Corked, ET Radials,. 11.33@117.72.
Same car, bone stock 346s, 9.5 comp, baby solid. 12.24@110.
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Re: Chapman Stage VI 260 questions
[Re: Von]
#241990
03/04/09 04:38 PM
03/04/09 04:38 PM
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Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
BradH
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Taking time off to work on my car
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Quote:
Quote:
Hey BradH just curious, what are they selling them for bare?
2600 bare, 2800 w/valves, 3200 complete
Those prices are not longer accurate, as of my call w/ Chapman yesterday. They're saying 2650 bare, 3000 w/ valves, and "it depends on what you want" for completed assemblies.
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Re: Chapman Stage VI 260 questions
[Re: AndyF]
#241991
03/04/09 04:40 PM
03/04/09 04:40 PM
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Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
BradH
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Taking time off to work on my car
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Quote:
On the dyno the motor would probably pick up 50 to 75 hp with that head swap, maybe even more.
Well... I played ("played" seems like the operative word) with my Performance Trends Engine Analyzer Pro software to try and get a feel for that. First I had to establish a baseline configuration that was reasonably consistent w/ the actual results the engine produced when dynoed up at Dwayne's back in 2003.
What I came up with cranked out 610 HP @ 6200 rpm and 571 torque @ 4800, both values within a few #s of the actual results. Then I "switched" to the Chapman 260cc Stage VI specs and re-ran it w/ no other changes... 671 HP @ 6400 and 607 torque @ 5400. It showed the torque curve taking a hit below 4000, which makes sense with the increase in runner volume.
I can't say how close this would be in the real world, but that's a big increase predicted for a basic head swap.
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Re: Chapman Stage VI 260 questions
[Re: BradH]
#241992
03/04/09 05:21 PM
03/04/09 05:21 PM
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Joined: Jan 2003
Posts: 9,876
Weddington, N.C.
Streetwize
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Weddington, N.C.
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Brad,
Can you overlay the before/after charts?
I think what you would find "real world" is even though the runners are bigger the velocity won't slow much at all and the torque may even INCREASE down low...that's because the constant area in the port will prevent the air from bottlenecking which I think is inevitable with the Standard (Standard 906 length valves) stage VI which really pinches the roof to bowl transition.
when you minimize the bottleneck the result will be the cylinder will fill more completely (higher VE) and make more torque.
Last edited by Streetwize; 03/04/09 07:54 PM.
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Re: Chapman Stage VI 260 questions
[Re: BradH]
#241993
03/04/09 07:29 PM
03/04/09 07:29 PM
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Joined: Oct 2003
Posts: 3,698
NE Oklahoma
Von
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NE Oklahoma
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Quote:
Those prices are not longer accurate, as of my call w/ Chapman yesterday. They're saying 2650 bare, 3000 w/ valves, and "it depends on what you want" for completed assemblies.
Guess they went up. That is what they told on Dec. 23.
72 RR, Pump gas 440, 452s, 3800 lbs, Corked, ET Radials,. 11.33@117.72.
Same car, bone stock 346s, 9.5 comp, baby solid. 12.24@110.
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the seller. I told him to let me know if the deal falls through. 
...
