Re: Another Carb question...
[Re: Thumperdart]
#2414858
12/07/17 07:17 PM
12/07/17 07:17 PM
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Joined: Jul 2005
Posts: 153 Bradenton, FL
Benforsp
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You have to to in order to have a base tune and to know what needs to be changed to bring it around to your cars needs...........no other way........ Thumper, What all is involved in this and what specialty tools are needed?
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Re: Another Carb question...
[Re: Benforsp]
#2414883
12/07/17 08:04 PM
12/07/17 08:04 PM
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Joined: Jul 2004
Posts: 19,318 State of confusion
Thumperdart
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We need to talk, too much to type..........
72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
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Re: Another Carb question...
[Re: Benforsp]
#2414948
12/07/17 10:16 PM
12/07/17 10:16 PM
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Joined: Jan 2003
Posts: 14,506 So. Burlington, Vt.
fast68plymouth
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-> 440-ish cubes with "big" heads that work better on 500+" -> moderate CR -> 260+ at .050" street roller -> limited stall speed -> street-tuned(?) carb w/ 1.56 venturi & downleg boosters
Those are my thoughts as well. 1.56 venturi downleg carbs can be a real challenge to "tune the bog out of". IMO, I think a main body swap to something with a smaller venturi would ultimately yield better results(I'd probably use a 1.400 x 1.750)....... But if I were trying to work around that combo, I would expect to have to run fairly large squirters, and probably a 50cc pump/cam on the secondary side, and I would absolutely ditch the 2.5 pv. You want to get a head start on the main circuit enrichment when going to wot...... It would get a 6.5 if I were messing with it. There is a lot of plenum and runner volume in that combo, and not a lot of cubes generating signal.......... It's going to need a lot of help(pump shot) to give the motor something to work with until the main circuit is activated. Not what you asked, but there is some performance left on the table with that cam, in that combo.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Another Carb question...
[Re: BradH]
#2414966
12/07/17 10:52 PM
12/07/17 10:52 PM
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Joined: Jul 2004
Posts: 19,318 State of confusion
Thumperdart
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I Live Here
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We need to talk, too much to type.......... with one finger You know me too well...............lol
72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
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Re: Another Carb question...
[Re: fast68plymouth]
#2415165
12/08/17 12:19 PM
12/08/17 12:19 PM
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Joined: Jul 2005
Posts: 153 Bradenton, FL
Benforsp
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-> 440-ish cubes with "big" heads that work better on 500+" -> moderate CR -> 260+ at .050" street roller -> limited stall speed -> street-tuned(?) carb w/ 1.56 venturi & downleg boosters
Those are my thoughts as well. 1.56 venturi downleg carbs can be a real challenge to "tune the bog out of". IMO, I think a main body swap to something with a smaller venturi would ultimately yield better results(I'd probably use a 1.400 x 1.750)....... But if I were trying to work around that combo, I would expect to have to run fairly large squirters, and probably a 50cc pump/cam on the secondary side, and I would absolutely ditch the 2.5 pv. You want to get a head start on the main circuit enrichment when going to wot...... It would get a 6.5 if I were messing with it. There is a lot of plenum and runner volume in that combo, and not a lot of cubes generating signal.......... It's going to need a lot of help(pump shot) to give the motor something to work with until the main circuit is activated. Not what you asked, but there is some performance left on the table with that cam, in that combo. Fast, The carb had 6.5's in it and I can put them back in no sweat. I knew the cam was pretty big but had talked to some folks and they suggested it would be suitable, but I would consider other options, what might you advise?
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Re: Another Carb question...
[Re: Dadodgekid]
#2415169
12/08/17 12:24 PM
12/08/17 12:24 PM
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Joined: Jul 2005
Posts: 153 Bradenton, FL
Benforsp
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whats the fuel pressure set to... Kid, The fuel pressure is 6.5-7 PSI. I run an electric pump with a return style fuel system with -8 lines.
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Re: Another Carb question...
[Re: Benforsp]
#2415212
12/08/17 01:48 PM
12/08/17 01:48 PM
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Joined: Jan 2003
Posts: 14,506 So. Burlington, Vt.
fast68plymouth
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It would require a conversation before I would recommend any other cam, but I think getting rid of some seat timing would be a step in the right direction.
You said "pv's"....... If you're still running one in the secondary side, remove it and replace with a plug....... And jet up accordingly(around 8 sizes).
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: Another Carb question...
[Re: Benforsp]
#2415239
12/08/17 02:30 PM
12/08/17 02:30 PM
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Joined: Jul 2004
Posts: 19,318 State of confusion
Thumperdart
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whats the fuel pressure set to... Kid, The fuel pressure is 6.5-7 PSI. I run an electric pump with a return style fuel system with -8 lines. Still waiting for a call...........lower the pressure to 5.5 max IF you run .120 needle n seats which you should.......
72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
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Re: Another Carb question...
[Re: Benforsp]
#2415277
12/08/17 03:53 PM
12/08/17 03:53 PM
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Joined: Aug 2003
Posts: 43,251 Bend,OR USA
Cab_Burge
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You still haven't given any details of the cam or the carb's current tune. That doesn't make it any easier to try and help.
The 0-82951 is the "Street HP", right? Check the actual venturi diameter and see if it's 1.38" or 1.56" I've seen conflicting specs, depending upon when the carb was made I guess. The tune would likely vary quite a bit depending upon which size it is.
I have no first-hand experience w/ the "Street HP" stuff. I'd hope that they're "flexible" enough to be tuned to work w/ your combination. http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=739&sb=1Installed straight up with 1.6 ratio rockers to bring the lift up. Cam Detail.... Did you degree the cam or did you install it with the dots "straight up" ? If not degreed you should do that now I would advance it so the intake lobes are from 107 to 105 max lift after top dead center I've ran a very similar cam (260@.050 int., 266@.050 ex. ground on a 108 LC installed two degrees advanced on the intake lobes)) Comp solid roller with 1.6 ratio rockers, no bog even with a six pack set up after I had to sort it out. I had another bracket motor with a Holley 80496 950 HP on a TM7 intake with ported 906 heads and a bigger Crane solid roller and it never bogged ever, that cam was advanced 4 degrees
Last edited by Cab_Burge; 12/08/17 03:54 PM.
Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
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Re: Another Carb question...
[Re: Cab_Burge]
#2415298
12/08/17 04:46 PM
12/08/17 04:46 PM
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Joined: Jul 2005
Posts: 153 Bradenton, FL
Benforsp
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You still haven't given any details of the cam or the carb's current tune. That doesn't make it any easier to try and help.
The 0-82951 is the "Street HP", right? Check the actual venturi diameter and see if it's 1.38" or 1.56" I've seen conflicting specs, depending upon when the carb was made I guess. The tune would likely vary quite a bit depending upon which size it is.
I have no first-hand experience w/ the "Street HP" stuff. I'd hope that they're "flexible" enough to be tuned to work w/ your combination. http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=739&sb=1Installed straight up with 1.6 ratio rockers to bring the lift up. Cam Detail.... Did you degree the cam or did you install it with the dots "straight up" ? If not degreed you should do that now I would advance it so the intake lobes are from 107 to 105 max lift after top dead center I've ran a very similar cam (260@.050 int., 266@.050 ex. ground on a 108 LC installed two degrees advanced on the intake lobes)) Comp solid roller with 1.6 ratio rockers, no bog even with a six pack set up after I had to sort it out. I had another bracket motor with a Holley 80496 950 HP on a TM7 intake with ported 906 heads and a bigger Crane solid roller and it never bogged ever, that cam was advanced 4 degrees Cab, I had thought about installing it advanced and regret not doing so at this point. The cam was degreed.
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Re: Another Carb question...
[Re: Benforsp]
#2415303
12/08/17 04:54 PM
12/08/17 04:54 PM
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Joined: Aug 2006
Posts: 610 long time lurker, short time p...
PorkyPig
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long time lurker, short time p...
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You have to to in order to have a base tune and to know what needs to be changed to bring it around to your cars needs...........no other way........ Thumper, What all is involved in this and what specialty tools are needed? How much carb tuning experience do you really have? It sounds like you may be in over your head.
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Re: Another Carb question...
[Re: Thumperdart]
#2415304
12/08/17 04:57 PM
12/08/17 04:57 PM
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Joined: Jul 2005
Posts: 153 Bradenton, FL
Benforsp
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OP
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whats the fuel pressure set to... Kid, The fuel pressure is 6.5-7 PSI. I run an electric pump with a return style fuel system with -8 lines. Still waiting for a call...........lower the pressure to 5.5 max IF you run .120 needle n seats which you should....... I tried! No Answer.
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Re: Another Carb question...
[Re: Benforsp]
#2415327
12/08/17 05:47 PM
12/08/17 05:47 PM
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Joined: Jan 2003
Posts: 14,506 So. Burlington, Vt.
fast68plymouth
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I had thought about installing it advanced and regret not doing so at this point. The cam was degreed. If the cam was installed as per the cam card in the link you posted, then it's installed 4deg advanced. The advance is ground into the cam. Advancing it "more" isn't going to cure your problem.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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