broker.902

trying to get some info on 6 pack set up on 427 435hp 1969 corvette carbs all rebuilt center carb 3.5 power valve works great out side carbs work when manualy no sticking when tested with car not running I put a vacum pump on the hoses to the diapharms opened no problem Ichanged different springs still out side carbs wont open how can you check center carb for vacum signal while carb on or off car you cannot do this by reving engine thankyou Broker.902

MelWff

put a paper clip on rod going from diaphram to linkage. Drive the car with a few wide open passes and see if paper clip moved. Before you do this have someone sit in car with engine off and full depress gas pedal. Check if center carb fully opens.

broker.902

thankyou for the replay tried that no luck is there away to check center carb for vacum at the port where vacum hose plugs on for vacum diaphragms on out side carbs thankyou BROKER.

MelWff

use a vacuum gauge with a long hose and place gauge in front of you while driving, watch the gauge as you drive for any readings

broker.902

I will try tomorrow Iwill get back to you thankyou

7T1vette

If you want a 3x2 setup that is 'factory original', keep fooling with those vacuum diaphragms...and good luck. The '68 or '69 Chevrolet Chassis Service Manuals have the best instructions on how to set that up as built from the factory. If you don't need them to be configured like the factory built them, dump the vacuum actuators and put a solid/progressive [hard] linkage on them. Set it to operate on the center carb only until about 60% of throttle, then it should bring in the outer two, together, until all three carbs reach 100% throttle at the same time. It may not be as "economical" as the factory setup...nor have the same emissions performance; but, it will sure as he!! scream like a banshee when you open them up!

broker.902

I like that idea I,am getting tired of playing with them this car is all number matching w/ docks Iwill change over to solid linkage. With out primary pumps you think it would bog I might give it a try any idea where to buy the linkage without fabricating the linkage Thankyou Broker

7T1vette

About any good auto parts store should be able to order the linkage. Or you can try Summit or Jeg's. I don't know that any of the Forum vendors sell that kind of stuff, but maybe they'll chime in if they do. I think you will be happy with the change. You can still research the 'correct' way to set them up...I would suggest that you keep and identify every piece, screw, etc. off the set if you change the configuration. You never know when you may want to get it back to factory mode (show, display, ???).

broker.902

[QUOTE=broker.902;1577855519]I will try tomorrow Iwill get back to you thankyou Just did the test we have vacum 6in at 2500-3000rpm higher 4000 rpm 10ins.I found 3 issues the carbs were cadium plated the throttle shafts were also plated with the engine running out side carbs disconnected and engine warmed up shafts got tighter flicking the throttle plates while engine running seemed a bit tight To resolve this problem the throttle shafts would have to be lightly sanded The cam is a hydraulic roller cam cant remember specs something close to l88 cam low vacuum Stock cam would be 10to12ins of vacuum at idle I put white springs in vaccum pots .POTS started to open at 4000rpm so we have some thing. The right opening should be 2500rpms all the trouble is mostly due to low vacuum because of none stock cam.Some one sent a thread about a mechanical linkage set up this would resolve the problem but to make it come on progressively might be a challenge plus clearance issues on the dome If someone has done this it would be great to forward the info and show me or if low vaccum dosent matter tell me another way Thankyou Broker