OT: Carb question for car tuners.
 

When jet extensions are installed on the secondaries, is a jet change required? I just put some in a 850 DP and it now appears to be a little fat. I did not expect any change except under hard acceleration coming off the line. Thanks.

The purpose of jet extensions is to keep the jets in fuel under hard acceleration by enabling the carb to fed from the back of the bowl. So, it is very possible that in your motor, the secondaries were starving for fuel because the fuel was pushed all the way to the back of the bowl. It is more than likely that you will have to jet down a bit. I personnaly never liked them. I have seen them come off and bounce around in the bowl.

you may have to trim them to get them to work the way you want. my brother has a dragster that without them falls on its face when launching, but with full length extensions wont run on the big end. cut the extensions in half and it was perfect. never had to make a jet change. the exhaust temp didnt change a bit with the shortened extensions installed.

Holley makes a notched float to be used with jet extensions on center hung floats. You may be holding up your floats causing a rich condition. Check Jegs.com for the notched floats.