[Greg Reid]

I'll bet it was more fuel delivery related than timing. That's exactly the kind of thing that can happen using carbs that haven't been calibrated to your exact setup.

[RocktimusPryme]

Maybe. Im not here to argue about it because like I said results are going to vary. I was just saying that my small sample size experience has been that Q jets don't like full manifold. The carb for the Firebird was built for the car and actually ran really well....on ported spark lol. The only other issue I ever had out of that carb was that it ran out of fuel on the track until I went to an electric pump. I sold it when I went to FI and 100% honestly I wish I had it now to throw on the Catalina.


I did pop open the distributor for the Olds yesterday. I couldn't make the weights hang up but clearly some water had gotten in there at some point. There was plenty of corrosion. It was an original unit. Cap and rotor made in USA and a 990 module. I sprayed the advance unit a little to worked them out a bit. Then I took some sandpaper to the terminals on the cap and rotor.

[Greg Reid]

Oh, no argument intended...It sounds like the carb was set up for the engine and you know what your results were better than I possibly could!
I thought I was using ported vacuum on mine for years until I found that I didn't actually have a true ported vacuum on my 74 carb. I do get a slight pulse there when I first crack the throttle open so, I'm not sure what that's all about.
I've since moved it to full manifold vacuum and like it there better. I didn't have any dead spots or bogs in either position but I've noticed that it runs a little cooler with full manifold vacuum. 195 as opposed to 210-220 before.