84-Z28-Canada

Hi guys, I posted this is the Canadian section, but I wanted to post it to the whole board to get everyone's opinions. I posted that I was looking for a good used carb (600-650cfm) to run on my 305 for now and on my 350 when it's in. Both have dual plane aluminum intakes, the 350 is cammed. SO, I asked for some input, and somebody wisely told me that I should just have a q-jet rebuilt. The trouble with that is, the qjet (non computer controlled) looks like it's stupid hard to put back together properly (i'm not incompetent, I just really don't want to F*** with it and never have it the same way). Anyhow, knowing the qjets perform well....and knowing that Edelbrocks and Holleys can perform and be tuned just as well....Let me hear your thoughts. thanks,

Ian

84-Z28-Canada

oh, and, whats happening with the old q-jet right now. Works fine to start the car and idle. Even works great around town. Where the trouble lies is when I'm driving around 80km/hr to 110km/hr (about 50 - 65 m/h for you guys ) I'm bogging pretty bad and im getting kicks and spurts of power. Not exactly performance. Thanks again for the input guys
Ian

Awesome-X

There are a million and one rebuild tutorials on the site here, and there are always youtube videos and everything else to help you along the way. Quadrajets are also, for the most part, very cheap to buy. So even if you did manage to screw it up you could always buy a new one lol. On the other hand if you're looking for gas mileage/good performance I would go with an Edelbrock. I had a 1406 and got 27mpg highway with a 355 mated with a 700r4. If you want straight out performance go Holley.

84-Z28-Canada

I love the idea of performance along with fuel milage...thats a good suggestion, thank you. I keep hearing the same thing about holleys as well, best for all out but if you want a compromise than go stock or Edelbrock. I'm thinking that I might pick up an edelbrock 1406 (600cfm) and get that on the go, and in the mean time put the qjet back together.....then it doesn't matter how bad I mess things up!

five7kid

iTrader: (14)

Where is your timing set? How did you set it?

If the ignition is up to snuff and timing set properly, then I'd say you have a fuel delivery problem. There is about a 90% chance that changing the carb will not solve the problem (the other 10% is the fuel filter in the carb inlet is clogged up - which doesn't require changing the carb, but changing the carb will change the filter).

84-Z28-Canada

My timing is currently set at 16* base timing and 32* advance. I know that sounds nuts, but that is the only way my car seems to want to work. To set the timing after swapping out to an aluminum intake manifold (weiand 8004) I made sure that piston 1 was at TDC, put the dizzy back in place and made sure the rotor was pointing toward number 1. Put all my wires back on and grabbed the timing light (digital) and put the connector around the number one ignition wire. when i tried setting the timing to base 8, the car was simply not having it (falling on its face). Even at base 12, the car would fall flat when I hit the throttle. I also had the throttle open and the motor around 3500rpm while I set the timing for the advance. 16 base time and 32 advance seemed to be working best. Now, I'm having a distinct lag and kicks and spurts around 80-100km/hr. I really don't mind the q-jet, as long as it works properly. I think I could change the fuel filter without much difficulty, do you think that will make a difference? thanks again -> Ian

five7kid

iTrader: (14)

Did you have the vacuum advance disconnected when you set the timing?

It might be the fuel filter. Do you just have the one in the carb inlet, or is there one in-line? Could also be the fuel pump, or a clogged pick-up sock in the tank.

84-Z28-Canada

I did have the vacuum advance disconnected when I set the timing. I'll start with the fuel filter as that might be the easiest solution. It wasn't acting like this before I swapped the intake manifold and moved the carb all around. Perhaps something in the filter got knocked loose when I had the carb off and on again. I'll update after I get the filter swapped. thanks for your help so far

TreeFiddy

Often overlooked - you changed the intake and pulled/replaced the carb, but did you pay attention to the carb flange gasket? I've had odd symptoms caused by leaks there, when re-using the old gasket that looked ok.

84-Z28-Canada

Hi guys, thanks very much for the input so far. Yes I had considered the carb gasket, so I got a new one when I put the carb back on. I changed the fuel filter last night, but I have yet to get out and drive the car so I can't tell you whether or not the change has been effective. Let's be honest though, probably not just the fuel filter lol... Either way. I will get out and try driving the car. starts beautifully, but when I get it over 80km/h it's like it gets a little choked. SO, i'm going to try a different carb or rebuild the qjet. BUT the big(ger) motor is going in next weekend....so I'm wondering if I should just wait and do it then. Gearhead problems right? have a good weekend guys

travis401

iTrader: (1)

if you do plan on switching carbs youll have to take into account that the qjet is a spread bore carb, most holleys and edelbrock carbs are square bore. so to run one on the intake you have, youd have to use an adapter.

five7kid

iTrader: (14)

The 8004 can mount either a square bore or spread bore carb.

travis401

iTrader: (1)

i knew some were both square and spread bore, just didnt know if that one was.