2bbl linkage on a 4bbl carb----will it do any damage to drive?

[69bronzeT5]

I'm really considering driving my Duster down to the Mopar show in Everett on Sunday but one thing concerns me. My 318 originally was a 2bbl but now it's got a Holley 4bbl. I still have the stock 2bbl throttle/kickdown linkage on it. I've been having issues with the carb not opening up when flooring it. It's a 4bbl so it should get up and go......well somewhat considering it's still a 318 However it doesn't. It's pretty much only running on 2bbls. I've heard the Lokar throttle cable is the way to go and will cure my issues. One guy mentioned to me at a show that it could kill my transmission if I don't ditch the 2bbl linkage for the Lokar cable. The Mopar show in Everett is about 150km's (90 miles) from home each way give or take. Will it damage my transmission or anything else rolling with the 2bbl linkage for that distance? I cruised around all summer with the 2bbl linkage but just within town, nothing really too far. If I do go I may try to take side routes and avoid the highway but it seems alright on the highway so far.

[Kern Dog]

You will hear many guys tell you that the trans will cook quickly with a maladjusted kickdown linkage. Truthfully, it is called a throttle pressure rod, but the "kickdown" name seems to be the accepted name nowadays.
I have always tried to keep all my Mopars trans KD linkage working correctly. I have a 74 Dodge truck with a 440/727. The upshifts had been getting softer and softer and I figured that the trans was nearing its last mile. I drove it like this for HUNDREDS of miles, towing and hauling thousands of pounds of dirt, trash, metal, all sorts of stuff.  Last month I was underneath to fix a leak and noticed that the lever on the trans that operates the KD feature had slipped off and was free to move around regardless of what the throttle was doing. I connected it and the trans shifts as firm as any rebuilt trans I've seen. A trans in good condition is very durable. This is in no way a suggestion to purposely ignore factory recommendations. The linkage should be in place and functioning properly.
The throttle lever on the carb should push on the KD rod the instant that the gas pedal is pressed, and the trans kickdown should NOT stop the carb from reaching full throttle. The range of travel of the carb needs to match the trans. This will give you better upshift quality and extend the life of the trans.
FORGET the Lokar cable. Contact Bouchillon for theirs. Its based on Mopar parts and comes with clear instructions. I have their kit in my Charger. ZERO problems.
Finally... If you are not getting the secondaries to open, it shouldn't be too hard to fix. Holley carbs are pretty simple. I didn't see a CFM of the carb that you have, but the 750 models have a pod on the right side that houses the spring that delays the opening of the secondaries. You do NOT want the secondaries to open at 1200 rpms. The Holley engineers are no dummies. They make a kit with different springs to move the rpm point at which the secondaries will open. Other factors can affect inoperable secondaries: vacuum leaks, bent linkage or an improperly adjusted throttle cable. Good luck and keep us informed!

[69bronzeT5]

Thanks for the advice and info, I really appreciate it! So do you think it will be fine if I just cruise and take 'er easy? The transmission always shifted strong with the 2bbl carb so I'd say it's in great condition.

[1969chargerrtse]

For 3 years I didn't have my lickdown lingage connected.  I just fixed it this year.  If I took off slow I let the trani shift.  If I took off fast I shifted the trani myself, that simple.  What people mean is if you don't have the kickdown lingage hooked up and working correct and know nothing about mechanics and every time you took off and the trani just automatically shifted you would be putting a hard load on it.  Just shift the postions from 1 to 2 to 3 yourself under loads and you will be fine.  If you are slowly taking off it probably will be ok to let it automatically shift it's self.   You'll hear and feel what's going on to know what's good or not good as you're driving.

[Kern Dog]

Thanks for the advice and info, I really appreciate it! So do you think it will be fine if I just cruise and take 'er easy? The transmission always shifted strong with the 2bbl carb so I'd say it's in great condition.

I did send a MIXED message, so I'll clarify: While the trans isn't likely to grenade, it certainly isnt a good idea to drive very far with the linkage out of adjustment. Its like running an engine low on oil, a tire half inflated or an old condom. Sure, you may be okay, but at what cost?

[Brass]

I would get it fixed properly asap.  That being said, I'm guessing the greater danger to the transmission is probably driving around town.  The freeway might actually be a little safer where it'll stay in third gear and won't be short-shifting.  But such a trip would require plenty of 1-2-3 shifts at either end so there's still a risk.  Good luck with whatever you decide.