Just out of curiousity, how do the later model Q-Jets (with the electronics) compare to the early 70's models? Will they work on our cars? Same CFM?
The later model Q-jet with the electronic controller is not as adjustable as the erlier versions. They can be made to work ok but you are far better off going with a Q-jet from 1977 or 78 they are considered to be the second generation and have some improvements over the erlier carbs like the one that came on your car. One nice advantage is the electric choke. also you can adjust the off idle mixture from the top of the carb instead of messing around with the base plate of the carb. Just my 2 cents
Trudi. I have a 76 model 800cfm Quadrajet that was originally meant for a Big Block Pontiac. I had to make a few mods to the linkage and I adjusted the secondary metering jets and hanger and it goes great. Read all (all 4 that is) articles on the net regarding quadrajets and you will make a wiser decision.
I agree, anything from 70 - 78 is a viable choice. But remember two things.. In '71 BBB started 800cfm, '72 all were 800cfm. In '75 I think, they cast more metal into the secondary arm thing so they only open about 40 degrees or so instead of 90. You can of course 'cure' that with a saw, file, etc.. :Brow: Personally, I like the non epa'd versions so, 70-72.. :grin:
Bil, Can you post links? I've read some stuff, but with so many search results I don't know if I hit the ones you mention. Scott, I was wondering about things like the secondary rod, and if the mods are easy, that broadens my choices.
Quick little tip about those rods :laugh: just take some wire and thread it between the carb and arm to hold the arm up....DO THIS ONLY WHEN RACING!! twist the wire together to stop it from dropping through the carb and the secondary rods should be up....what this does is allow the secondaries to run a bit richer, which is a common prob with q-jets (they usually lean out when you stomp on it). Just a little friendly tip for ya :TU: Larry :TU:
Truzi, I'd be lieing if I said I've done any mods to my carb other then putting in some new edlebrock parts. The thing has a bog that seems incurable that I've just given up on. Hopefully for B-Day or X-Mas someone will give me a carb blueprinting session... :Brow: Bill has several links on Buickstreet, and there's the ever so popular Rochester book by Doug Roe... The book does show how to fix the secdonaries on the epa'd carbs.. Soo......
Larry have you ever adjusted the primary metering rod height? This is for off idle fuel mixture and can make a HUGE difference. I couldn't get my engine to idle properly until I found a shop that could adjust this for me properly. I went from a bog at light throtle to tire burning performance. What a difference.
Well on my carb, its already adjusted for no hessitation what so ever when you nail it...I have an excellent carb guy here who races with Q-jets all the time...Just ask 70Voom (Ray)..I gave him a ride last week and he is extremely impressed that my car moves out like it does with no bog or hesitation. Not bad for a 350 thats over carbed :laugh: I only suggested that for people who have hesitation problems and its a temp fix for racing. Sorry for the confusion Larry :TU:
