Cliff's Quadrajet Parts and Rebuild Kits

General Category => Quadrajet Carb Talk and Tips => Topic started by: jlutz455 on March 29, 2016, 06:38:04 PM

Title: 73 Trans Am Quadrajet ported vac. port question..seems blocked
Post by: jlutz455 on March 29, 2016, 06:38:04 PM
Hi,

I checked the small port to the right of the fuel inlet ( as viewed if standing in front of car looking at engine) with a vacuum gauge at idle and driving around. There's no vacuum at all making me think it's been blocked.  I want to hook this port up to my MSD distributor but where should I check if this is blocked and can I drill it out ?  Carb # is 7043263

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Title: Re: 73 Trans Am Quadrajet ported vac. port question..seems blocked
Post by: jlutz455 on March 29, 2016, 06:40:30 PM
forgot to add the vacuum line that is under the idle solenoid bracket is where the distributor is connected.
Title: Re: 73 Trans Am Quadrajet ported vac. port question..seems blocked
Post by: Cliff Ruggles on March 31, 2016, 03:26:49 AM
Remove the baseplate and verify that the passage leading up to the fitting isn't blocked.

Look at the baseplate to make sure it has a vacuum supply just above the throttle plates that leads to the same passage.

If someone installed the wrong baseplate it may not be drilled for ported vacuum.....Cliff
Title: Re: 73 Trans Am Quadrajet ported vac. port question..seems blocked
Post by: jlutz455 on March 31, 2016, 10:59:35 AM
Ah..makes sense. I'll check this weekend. Thanks Cliff!
Title: Re: 73 Trans Am Quadrajet ported vac. port question..seems blocked-fixed!
Post by: jlutz455 on April 07, 2016, 11:28:26 AM
wanted to update... Looks like my baseplate on my car is from an auto trans car as it has a port for the auto transmission modulator to the right of the EGR port.

The ported vacuum port in the body didn't connect to the baseplate so referencing another post in this forum, drilled a .050" hole just above where the throttle plate opens (referenced the other side primary horizontal slot position as to where to drill) Now I have ported vacuum as verified by a vacuum gauge and a vacuum "T" while driving.  I get 10-12 in of vacuum now at part throttle cruising. Thanks Cliff :-)
Title: Re: 73 Trans Am Quadrajet ported vac. port question..seems blocked
Post by: unruhjonny on April 07, 2016, 11:47:32 AM
I was just going to say - that's a manual transmission carb number - which shouldn't have a port there.

I believe that's a 1973 400/manual transmission application carb.