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Author
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Topic: Switched to a holley strip dominator - problems. Advise please
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Built351c
Gearhead Posts: 117
From: Big Lake, MN
Registered: Dec 2001
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posted 07-24-2003 08:25 PM
  
My motor is more then enough for the intake, but I have a feeling I might have to switch the gears in the back of the car. I had a Weiand X-celerator on the car. With the 850 Mighty demon things seemed nice and crisp. I switched intakes now the motor is doging a little bit and sputting a little bit going at slow speeds. I lost the bottom end of the motor. Before I could just tap the gas and the tires would smoke. Now it just acts like it wants to bog. Current gears in the car is 3.89's. 4000 stall. For those who dont know my build here it is:: 1970 351c .20 overbore
: 2- bolt mains studded with ARP Main stud kit
: Blueprinted, balanced
: Linehone mains
: Index block and Torque Hone block with deck plates
: Shotpeen and Resize rods and install ARP bolts
: Hone Rods for full floating pins
: Drill rods for pin oiling
: Static and Spin Balance
: Prep Crank
: Polish & Chamfer crank
: Grind Crank .020-.020
: File fit Z-Gap Rings
: Lunati Custom Light Weight Pistions
: Lunati Solid Roller Cam
: The spec's:
: Lift at valve
: .650 In. and .650 Ex.
: Duration at .050 Tappet lift
: 260 In. and 268 Ex.
: Advertised Duration
: 293 In. and 307 Ex.
: Valve Adjustment
: .026 In. and .026 Ex.
: 108 Lobe separation : 351 4v 1970 closed chamber with a mild clean up flowed these numbers.
: INTAKE
: .100-70cfm
: .200-132.8 cfm
: .300-192.6 cfm
: .400-242.8 cfm
: .500-278.4 cfm
: .600-293.0 cfm
: .700-301.0 cfm
: .800-301.0 cfm : EXHAUST
: .100-56.6 cfm
: .200-103.6 cfm
: .300-143.5 cfm
: .400-173.9 cfm
: .500-195.3 cfm
: .600-203.5 cfm
: .700-206.6 cfm
: .800-208.5 cfm :
: 1970 Closed chamber heads
: Hardened Alloy Valve Guides
: Hardened Exhaust Seats
: Stainless 2.190 Intakes Valves
: Stainless 1.750 Exhaust Valves
: 11/32 Full Bronze valve guides
: .030 Hardened Lunati shims
: 11/32x.500 Postive teflon valve seals
: Vasco Jet Roller springs
: Lunati Titanium Retainers
: Lunati Spring cups
: Lunati Machined 10 degree Locks
: ARP Screw in rocker studs
: Manley Guide Plates 3/8
: Lunati Roller rockers 1.73
: Lunati stud poly locks
: Lunati pro-series push rods : Carb - Mighty demon 850
: Intake - Wieand X-celerator/Now holley strip dominator.
: Headers - Hooker supercomp 1 7/8
: C-4 - 4000 stall
: 3.89 Traction-Loc.
: 3inch with X-pipe Dyno-max Ultra-Flow duel exhaust. - Sounds Sweet. : Car: 1969 Mach 1 - 3240lbs w/o driver.
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Dad Vishus
Gearhead Posts: 856
From: Moscow, Iowa, USA
Registered: Dec 2001
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posted 07-24-2003 09:15 PM
Is this a street car?You don't mention fuel delivery system specs. That of course is not the bog problem, but this is almost a pretty potent race setup. I'm really kindof surprized that it can be street driven now. I'd say as to the bog, it ain't no grunt motor. If it were a drag car, I'd say looser converter and waaaay more gear. You don't mention compression ratio, but if its 10.5 or better its a perfect candidate for alky. Anyway, I digress.  I don't pretend to know much about Demon carbs, but I assume they can be adjusted. Your Strip Dominator is alot different style intake. The attributes are for running wide open, pretty much. No low end power is moot when a 60000 stall is in use. That cam sounds like one of the Lunati grinds we've used. KV could verify that. If so, that cam is good for 7500 RPM at least. It'll make a bunch of power. Enough to start breaking cylinder walls! ------------------
63 Falcon 377 Cleveland stroker Flying Toilet alchohol injection. 6.19 @ 110 MPH 1/8 mile
2002 Ranger FX4 daily driver
2000 F350 PSD Crew cab dually - Like commuting in a B52!!
98 US Cargo Phantom II 28'
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kid vishus
Gearhead Posts: 6220
From: middle of NC
Registered: Oct 2000
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posted 07-24-2003 10:46 PM
If you have hood clearance you might try a 4 hole spacer to try and get back some velocity. I'm sure the larger plenum and bigger runners is causing your problem. I'm also sure a gear change would show the greatest improvement as it would allow it to rev quicker. Your carb may need some fune tuning for the different intake too.I ran that same camshaft for several years. It works pretty good. It makes good power up to around 7 grand, but doesn't fall off much up to 7500 (just doesn't go any faster up there).
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clevelandstyle
Gearhead Posts: 1098
From: Connersville, IN
Registered: Jul 2001
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posted 07-24-2003 10:59 PM
I just changed from a Torker to a Strip Dominator, also. I didn't have the problems with the engine bucking like you did at low speed, but my cam isn't as big.(yet) 
I did loose some bottom end power, if you can call it that. I have a 4900rpm stall. My 60' times slowed about a tenth. This past week I changed my gear ratio from 4.11 to 4.56. I haven't run it at the track with the new gears yet, but I'm expecting to get some of my 60' back.
The Strip Dominator did gain me a little MPH, so I know it's making more power. ------------------
Ben
Grabber Green '70 Mach I 351C 4V
Robbin Egg Blue '79 Fairmont 351C 4V
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Built351c
Gearhead Posts: 117
From: Big Lake, MN
Registered: Dec 2001
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posted 07-25-2003 01:03 AM
The compresson is 11.3. The fuel line is 1/2 inch. Using the Holley Blue fuel pump. Fuel pressure set at 7 1/2 lbs. Car idles right at 900 rpms and drops to 700 rpm in drive. Yes I drive it on the street very limited though. Race gas is not cheap. Hey kid what size spacer would you suggest. A 1" spacer or a 2" spacer. I have the stock hood, but there is plenty of room for a 2 inch spacer. Again Thanks everyone for your advice.
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kid vishus
Gearhead Posts: 6220
From: middle of NC
Registered: Oct 2000
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posted 07-25-2003 08:06 AM
I have a 2" open spacer on mine, but, I also have a 6000 rpm convertor so low end torque isn't a major requirement. I would try a 1" 4 hole first on yours, and see if it helps, then if it does, try a 2" 4 hole. With that intake you might need to turn the idle up a bit. I have mine so it idles around 900-1000 in gear. If that doesn't help, then you may need a little work on the carb, stuff like air bleeds and other things I know nothing about.
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Hemikiller
Gearhead Posts: 618
From: Killingworth, CT
Registered: Feb 2002
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posted 07-25-2003 12:20 PM
By going to the SD, you increased your plenum volume considerably. Have you tried a larger acc pump squirter, or a quicker pump cam? You may also have to re-jet, and a spacer, as mentioned above, might be in order.
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jkilroy
Gearhead Posts: 1808
From: Vicksburg, MS
Registered: Dec 99
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posted 07-26-2003 09:15 AM
Let me second Hemikiller, you need to spend some quality time with that carb. A larger pump shot is almost certainly required.------------------
Jay Kilroy
68' Fastback GT 390
"No such thing as a cam thats too big"
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Built351c
Gearhead Posts: 117
From: Big Lake, MN
Registered: Dec 2001
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posted 08-02-2003 07:46 AM
Think I found the part of the problem. The holley blue fuel pump just died in my driveway. Hot to the touch and the car was only run for 10 minutes. Time for a new fuel pump.
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