69 QJet Tuning

[David S.]

Hi Guys,

Just installed an original Qjet on a 69 Corvette. Can anyone provide insights how to tune it.

Thanks,
Dave

[Terry M.]

Re: 69 QJet Tuning

There are several pages of instructions, with pictures in your copy of the 1969 Chevrolet Chassis Service Manual (CSM). There is a whole section entitled Tune-up written by the engineers who designed you Corvette. It will give you more information that a dozen of us can, and is available from the NCRS STORE via the radio button on the blue bar at the top of this page.

Some folks, whose focus is driving rather than judging, prefer to connect the vacuum advance to a full-time port. This can be done but then most of what I have offered above will need "tweaking." I am sure we will hear from those folks in due time -- but in the mean time you might tell us all what your focus is.

[Mike F.]

Re: 69 QJet Tuning

or you could try this.
http://www.lbfun.com/warehouse/tech_...ng%20Paper.pdf

[Clem Z.]

Re: 69 QJet Tuning

Hi Guys,

Just installed an original Qjet on a 69 Corvette. Can anyone provide insights how to tune it.

Thanks,
Dave

unless the carb was restored by a well know restorer i would check the jets,primary rods and the secondary rods to make sure they are correct.

[Don W.]

Re: 69 QJet Tuning

You can look at this document...Don

http://www.corvettefaq.com/c3/QJetTuningPaper.doc

[David S.]

Re: 69 QJet Tuning

Thanks all. It seems to be a vacuum problem. A slight whistle at idler (base plate gasket?) and upon shutting off the car a hissing as vacuum pressure is realized (is that normal?).

Also I have to set the timing since the car runs better without the vacuum advance connected.

Dave