Join Date: Dec 2002
Location: Fairfield, OH, USA
I had the same problem with my original DZ carb. I rebuilt it, but accidently stripped the threads for the float adjustment on the primary fuel bowl. I didn't feel like spending $60 for a new fuel bowl plus I had a brand new carb sitting in the garage.
I basically moth balled the DZ carb and put on a brand new Holley 650 mechanical secondaries double pumper. It ended up working great out of the box. If you're looking for something that's better on gas mileage, I think the consensus will say that you should stick with a vacuum secondaries carb.
If you're carb isn't in too bad of shape, you should be able to rebuild it yourself for much less than the cost of a new carb. It's not too difficult to rebuild one and it might be worth a try. Just some food for thought.
If you're looking for something more original, brand new carbs, exactly like the original DZ, are available, but they were around $500 to $600 the last time I checked, which is pretty darn expensive in my opinion.
Basically you have a few options to choose from. As far as carb size, your original carb is a 780 cfm, but I think a 650 will be sufficient, if you want to buy another carb. I've run mine, with the 650, up to nearly 7,000 rpm with no fuel starvation what so ever.
Would mine run better with a larger carb? Maybe in the quarter mile, but for street driving, the 650 should give better throttle response.
Good luck, let us know what you decide!
1969 Z/28 fathom green X77