Q-jet carb

[aknight_sa]

hi all,

i have a question about the carb installed on my Big Block engine..

its Rochester Quadrajet identification number is 17080213 then there us (3263 CPX), i have read in some pages on the net that this carb is for 350 engines.. not for 454... is this true? and how much CFM does this carb give?

thanks

 

[ryan22re]

170 = Rochester carb, 1976 and up
80 = 1980
2 = 49 state emissions
1 = Chevrolet
3 = manual transmission

I would say it's a 750 cfm, because its a chevy, but I dunno for sure. As far as I can tell there are no differences between the sb and bb carbs from that era (1976 and up).

 

[aknight_sa]

is there a difference in the models for manual and auto transmission carbs??

 

[dyeager535]

Almost every single Q-jet out there is different in one form or another, but an obvious physical difference? Not likely.

There is a way to tell the CFM on the carbs It is either a 750 or 800CFM, typically plenty for any stock/moderate engine build.

There is a link to Quadrajet info (including the difference between 750 and 800 CFM units) on my website, linked below.

 

[aknight_sa]

thanks for info and good info you have on your site..

this might sound like a silly question.. in the ID number of the q-jet the last digit is for either an even or an odd number which means euther auto or manual transmission... is this refered to the car's transmission or the choke as manual or electrical??

 

[dyeager535]

transmission

choke variations were pretty extensive among the various divisions

 

[aknight_sa]

would it make any difference if a manual transm. carb was installed on an auto transmission car?

 

[dyeager535]

Probably not that you'd notice.

Something was more than likely different, such as the air valve tension or power piston spring.

 

[diesel4me]

one more thing..

Most "manual tranny" carbs lack the hookup for the detent cable for an automatic too..can be added though,using parts from a carb that was meant for an automatic..most of the Q-jets I rebuilt on manual tranny trucks had slightly richer jetting than those used on an automatic tranny..