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My Six Pack doesn't pull like a Six Pack

moparcanuck

Deceased, But not forgotton
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Location
Ottawa,Ontario
Stock 440 with a Six Pack setup runs great in the city and on the highway. But when you punch it, it pulls ok but it just doesn't seem to pull like a Six Pack. Suggestions?
 
Stock fuel pump. Fuel filter is on lower front passenger's side of block.
 
Are the secondary diaphragms in good shape and opening fully?
 
Have you owned a 6 pack before?
Have you ridden in a 6 pack before?
If so, was it stock or modified?
Do you believe the build specs you were told?

How is this ride tuned?
And it's build specs?
How old is the engine build?
 
How's the primary throttle cable adjustment? Discovered my throttle cable was out of adjustment, and after we adjusted it the car had a noticeable improvement.
 
Stock fuel pump. Fuel filter is on lower front passenger's side of block.
on the suction side of the pump (between tank and pump)?

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I ordered them from from Holley. As far as I know, they are opening fully but how can I tell?
you can't, unless your on a chassis dyno and are watching them. if they're working properly you'll know it. make sure the vacuum connection at the center carb for the end carbs is connected to the tube coming out of the carb body.
 
on the suction side of the pump (between tank and pump)?

Not sure but I think it's between the pump and carbs. Car is in storage. Where should it be?

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you can't, unless your on a chassis dyno and are watching them. if they're working properly you'll know it. make sure the vacuum connection at the center carb for the end carbs is connected to the tube coming out of the carb body.

Yep. Just checked some pics of my setup.
 
filter goes on the pressure side of the pump; between pump and carbs. i'm not sure about todays replacement fuel pumps. the hipo 440's had a special 8+lb pump. the lopo 440's and 383's had a 5lb pump. i've been under the impression that the 8lb pump hasn't been made for decades. you need to check the fuel pressure to see what you have. for me the 6-pak lazy syndrome has been the lack of fuel supply. check rubber connections at the tank for any kinks or cracks. i prefer the 3 valve carter pumps over the stocktype 2 valve pumps. also, heavy springs in the diaphragms will slow them down. factory springs for '69 carbs were purple and '70-'71 carbs had yellows.
 
filter goes on the pressure side of the pump; between pump and carbs. i'm not sure about todays replacement fuel pumps. the hipo 440's had a special 8+lb pump. the lopo 440's and 383's had a 5lb pump. i've been under the impression that the 8lb pump hasn't been made for decades. you need to check the fuel pressure to see what you have. for me the 6-pak lazy syndrome has been the lack of fuel supply. check rubber connections at the tank for any kinks or cracks. i prefer the 3 valve carter pumps over the stocktype 2 valve pumps. also, heavy springs in the diaphragms will slow them down. factory springs for '69 carbs were purple and '70-'71 carbs had yellows.
X2, I had the same issues years ago with my 6BBl and it turned out to be low fuel pressure caused by the vapor separator. To much fuel was returning back to the tank, and the car would run out of fuel at the top end of the track. It would run fine, but just got real light on power.
 
those after market vapor separators have too large of a return orifice. i soft solder the return hole up and drill a .035" hole.
 
This is kinda vague. When my friend John cracks the 6 on his 'Cuda the best description for me is "scared.
 
What kind of fuel are you using? Are you running any 100 or 110 octane thru it or strictly pump gas? Mine loves racing fuel and moves around better with it every now and then.
 
Check the throttle cable to make sure its functioning properly and center carb is opening all the way.
 
I ordered them from from Holley. As far as I know, they are opening fully but how can I tell?

If they're opening fully, there's no mistaking it.

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Could be a lot of things. What do you know about the engine? Did you build it? Did you degree the cam? What cam does it have? What's the cam timing? What ignition timing are you running? Are the carbs adjusted right? Does it have the right springs? What transmission? What rearend gear? What tire height? The possibilities are endless.
 
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