What is the cfm of the carb on my 86 Cadillac Fleetwood brougham stock??

 

It is probably 750 cfm BUT the secondary opening is very limited. It can be fixed to fully in 5 minutes by bending the tang that limits air door opening.

 

Super simple. If it's an original E-carb, look down the primaries. If you see what looks like a baby bump in the casting, it's an 800 (rating). If not, it's a 750 (rating). Also, the 800 venturi isn't as skinny as the 750 and doesn't stick out from the walls as far.

Here's an 85 442 carburetor- note baby bump down on the left and the larger venturi.

 

Thanks now I can make sure it will work on the new 8.4 comp olds 350 engine..

 

You do know the stock carb on an 86 is computer controlled, right? To get it to run correctly on a larger engine you need to burn a new PROM.

 

First time I heard that,How you do that?

 

The computer controls both the carb and the distributor. Ignition advance curve will also likely be wrong. Creating a new PROM with new fuel and spark maps requires software and a PROM burner as well as a supply of new PROMs. Since this is a trial-and-error process, you'll use up a lot of PROMs until you get it right. You MIGHT want so consider deleting the computer and getting a conventional Qjet and distributor.

The prom is inside the computer, under a removable plate.

 

Joe, others have done it without a new PROM, including running a 403. Would a custom PROM be best? Absolutely. First, he needs to make sure everything in proper working condition before this swap. Vacuum lines replaced if weathered and no codes. Many have eliminated the air system with the CCC without issues. He can't run it unless the 350 heads are drilled tapped for the air tubes anyways. He is just going to be just over 8 to 1 with a mild cam with an appropriate LSA. If it runs like ***** he can do the carb, distributor and lock up swap. Hopefully his mechanic is familiar with the CCC.