What is the CFM rating for a stock Q-Jet on a 305 in 1984?

 

Well, I will take a guess between 580 and 600cfm. Anyone out there know the real answer.

Auggie

 

"Rating" is a misnomer.

"Capability" is more like it. Some of them had the AV travel restricted so they would only flow in that range (mine wasn't). However, if you modify it so it will go full open per the tech article on the Board, it will flow at least 750 cfm.

It will flow more than a 305 can use, that much is for sure.

 

Some were restricted to about 600cfm, like 5-7 said, but an unrestricted one will flow 780cfm.

 

IS it a good idea to un restrick with a stock 305? What i am asking is, will it give me more power or will it just choke the motor? Stock 305

 

Five7kid is right. 99% of all Q-Jets can be made to flow 750 cfm by allowing the A/V to open all the way, but there are a few Q-Jets with larger primary's that will go to 780 cfm. I would allow the A/V to open all the way because your eng. will determan if they will be pulled all the way open.

Auggie

 

It will make more power IF the engine needs the exra air... the AV is opened by engine vacuum, so it will only open it as much as it actually needs to.

You got nothing to lose by un-restricting it though, even if it doesn't need it

 

Technically, the AV is opened by air flow (engine vacuum implies manifold vacuum), but that's the concept - the carb is as big as the engine needs it to be - up to about 750 cfm (and it's a rare 305 that can need 750 cfm).

The same "size" q-jet that feeds my 305 also fed my 396.

 

If it only opens as much as the engine needs it to why'd the factory restrict some of them?

 

There you go again, trying to apply logic to factory design...

 

AMAN:hail:

Auggie