I know that a lot of people tell me to put a 750 on my motor, but it seems too big. I calculated the minimum CFM from that equation and I got 608 cfm minimum. I was thinking of getting a 650 DP, but I don not want it to be too small. On the other hand I do not want to get a 750 and have it be too big and just bog all the time.

I would appreciate some suggestions and experiences with a healthy 350 and DP carbs.

I have a manual transmission, and the car needs to be very streetable.

 

Doesn't Holley make a 700cfm DP? Happy medium maybe?

 

http://www.holley.com/HiOctn/TechSer...nfo/P225A.html

With a 650, you'll have to have/keep the RPMs above about 1200 when you floor it to avoid bog. With a 750, above about 1500.

On the other hand...

You aren't likely to see much difference in power between the 650 & 750.

Use the formula to calculate minimum required CFM for power.

Use the chart to determine maximum CFM to avoid bog at a particular WOT RPM.

As long as you are between those two values, you'll be fine.

 

To expound from the above-mentioned link:

"If your car has a manual transmission, use the lowest RPM at which you use wide-open throttle. This must be a very conservative RPM (on the low RPM side, that is!) and should be found by observing your own driving habits in the vehicle involved. Watch your tachometer! The heavier the vehicle and the lower the numerical axle ratio (higher gear ratio) - the lower this RPM must be."