1970 Quadrajet 7040509 600cfm
 

Have a nice 600 cfm Quadrajet from 1970 California only manual transmission
$125 shipped
Came off a running truck 10 years ago, probably needs a rebuild it has been in a plastic bag in dry storage.

Re: 1970 Quadrajet 7040509 600cfm
 

ttt

Re: 1970 Quadrajet 7040509 600cfm
 

Bump

Re: 1970 Quadrajet 7040509 600cfm
 

I guess I'm ignorant off these. Could you explain what makes this one special? Are 600cfm Q-jets rare or uncommon?

Re: 1970 Quadrajet 7040509 600cfm
 

ttt

Re: 1970 Quadrajet 7040509 600cfm
 

Quadrajets only came in 3 sizes: 750, 800, & 840. 750s were used exclusively on all Chevrolets. 800s were used on later model Buick Olds Pontiac & Cadillacs. The 840s were a special Hi-Perf breed used only on Pontiac SD 455s for 1 year...1970. The 750s were also put into service on some 6 cyl applications made possible by using smaller Idle tubes & idle down channel & restricting the opening of the secondary airflaps. The 0509 carb you have listed originally came on a 70 truck with a 396 w/ manual trans & destined for Cali. Didn't mean to write a book or cause any problems in this thread but I've been using these carbs for years & thought it necessary to provide this information.

Re: 1970 Quadrajet 7040509 600cfm
 

Oddfire,
Thanks for the info, so is this a 600 CFM?
Here is a reference sheet but I don’t see a CFM identification column.

Thanks
Trip

Re: 1970 Quadrajet 7040509 600cfm
 

No...the airflow of that carb is 750cfm the factory controlled the metering for various engines by drilling the idle air bleeds, down restrictors and also the main jet/ metering rod combos. No matter what you've heard...there's no such thing as a 600 or 650 qjet. jamie

Re: 1970 Quadrajet 7040509 600cfm
 

7040509 CHEV 70 TRUCK 396 CALIF 78 49 7036019 BG 2.8926 4.2474

This is right off of Lars sight. The following info is what all these numbers mean:

Carb # Application Main Jet Main Rod Spring Sec. Rod Jet Area Jet Area

This does not however give the cfm ratings...that's just a given

Re: 1970 Quadrajet 7040509 600cfm
 

Oddfire,
Thanks for the expert info!