I am looking to replace the quadrajet on my 401 with a set of Dual Quads. Before I go spend the money on this setup, are there any advantages / disadvantges to this setup ? Thanks
Gas mileage is tops. Also, I have tried several carbs. and not yet have I ever been able to get it as smooth at idle as one carb. Performance will be a bit better than the Q. Big reason is when you open the hood and people pour all over it!
people just droul over the fact that its stock and most other set up look like there a add on. i had mine stole, valve covers intake carbs. everything that could go quike while it was in storage this past winter. with health reasons and such the car is just sitting now. tried a single 4 intake and such on it but it woun't run right. i bought another set up off of ebay this spring but it will never be the same as what came with the car if you know what i maen
I used to have the q-jet setup on mine. The q-jet guys will certainly disagree with my next statement, but after having that carb on my '66 for over 20 years, I can say from experience that the dual carters are much better. The top end is great, 1250 cfm vs. almost half that from the q-jet. The only problem is they MUST be set up correctly. On the other side of the coin, I have found the cold driveability to be a little better with the q-jet......(not enough to be the deciding factor)........and the electric choke kit on the carter's made a huge improvement for me. The trouble with the early q-jets is that they are prone to leaking from the lower carb body plugs, and also the plug near the fuel filter will come right out..........spilling gas all over the engine. Later carbs were designed so that plug was eliminated. Some cars have burned, it even happenned to me once but I was lucky it happened in the winter and the motor was not too hot. I suppose if you have a fairly new q-jet that has not been overtightened and warped or taken apart too many times and screwed up by someone who did not know what they were doing you would be ok to use it. If I didn't think the dual carters were the best I would not be running them on my car.:bglasses:
i know what you guys say about the offy but its what i have anyway im trying to pick the carbs and i just wanted an i dea of what would be good for it im thinking dual 600's, anyway i wonder how will the throttle response be with the duals and how will it be on the top end? my heads are ported with bigger valves and im going to be running roller rockers with either a t/a 30 or t/a 413-401 cam and 10:5.1 compression any response will be appreciated...
I own or have owned 3 dual quad 64-65 rivs, and 4 or 5 Skylark GS (65, 66), and the best combo for me (performance and mileage) was with the single AFB. I found my best bang per buck for a stock setup was recurving the distributor, installing 3.90 posi and headers. If you have access to it, check out the April, 1965 Hot Rod to see what Kennedy Bell/Reynolds Buick did to go into the 13's with stock 65 GS. Dual quads look cool, though. Dan
My two cents worth I've had dual carter afb's on my 66 gkylark gs for about three or four years. Couple of observations: 1. Gas mileage dropped by about 25% no matter how easy I drive. 2. The cooool factor is up about 125% no matter which angle I look at them from. 3. Open element air cleaners with K&N's (I use 6x3 inch) breather WAY better than stock two snorkel breather (which is very beautiful but very restrictive) 4. Top end performance demands proper jetting. If you use good breathing elements like I do, .095 jets in all four secondaries worked best for me. 5. Performance at idle is smooth in mine but this took a lot of patience. 6. Doesn't start as well as the single AFB did but starts OK. Overall, I picked up about 3 tenths of a second in the quarter compared to the single four. Took about four months of experimenting to get there though.
Re: My two cents worth Compared to my q-jet my gas mileage stayed about the same, I may have lost 1 mpg but it's hard to tell for sure. The best I ever did with the q-jet was about 14 hwy with a/c off and the best I can seem to do now is about 13 hwy with a/c off. That's with 3.42 gears. I have also found the idle mixture screws are harder to get right as compared to the q-jet, they seem to be more sensitive but run good around 1-1/8 turn out from closed. One thing I did notice is that on the front carb the accelerator pump spring helps return the throttle to closed.........if you don't use the center adjustment hole (the factory setting) it will tend to stick open a little at idle.
