Have original Q jet in my 71 455. Has had a rebuild kit put in it but not a complete refurbish/ overhaul. It's surging at idle and does not seen to be quite right under power. Cant find any obvious leaks or other issues Considering trying a spread bore Holley while I have the original Q jet overhauled. I know I will need an adapter (and possibly a different throttle cable?). Does anyone have any experience with the spread bore on a BBO ?

 

You should not need an adapter as its also a spreadbore. Surging can be caused by fuel dripping from the nozzles, improper air/fuel setting and/or timing issues.

 

i have one on my 406 sbc in my nova,i like it. probly would like it on my olds also

 

As noted, the whole point of the Holley Qjet replacement carb is that it bolts to a Qjet manifold without an adapter. Whether or not this is a good idea is a different issue.

I've run these Holley Qjet replacements and I have not been impressed. The fact remains that the Qjet is arguably the most advanced 4bbl carb ever designed. That complexity results in a very flexible carb that can be used on engines from 230 cu in to 500 cu in with no substantive changes to the carb, but also leads to frustration among those without the patience or skill to adjust it properly. Personally, I'd keep the Qjet and tune it correctly.

 

Agreed. A properly setup QJet is a set-it and forget it carb unlike my experience with Holly. Purchase another Qjet from JET or other new Qjet sources while yours is being rebuilt. Call their tech lines and explain what your doing. Have your cars specs handy, (Cam profile, vacuum signal, transmission, and rear gears etc..). The surging could be a couple of problems. Get the two well known QJet bibles Doug Roe and Cliff Ruggle. They explain in detail how to set up a Qjet and to trouble shoot problems without chasing your tail. Is your 455 stock or upgraded? Whats the vacuum signal at idle off the intake? How do the spark plugs read?

 

Gentlemen thanks for the input very much, the Qjet is staying put. I'm just going to have to get it correct. I knew just an install of a kit was no guarantee of making the tuning of the carb to the motor easy. I have listened to too many shade tree mechanics on this. I even called Mondello in Ca. and asked about there refurbishing service (ouch!). Rockauto offers a refurbished Qjet to fit my application at a very resonable price that will probably work as a temporary unit. Looks like I'm going to be doing some reading and adjust my learning curve. Thank you again for the info

 

Contact Ken Gies at Everyday Performance.


Q-Jet guru with great service and pricing.


Top notch after sales support too.


http://www.everyday-performance.com/

 

I've used Ken in the past & was pleased.
Allstate is another good place.


http://www.allcarbs.com/

 

Another couple of good rebuild services are JET and The Carb Shop

http://www.customcarbs.com/

http://jetchip.com/product-category/...e-carburetors/