I've got a modified Nikki, it's got mechanical secondaries and enlarged venturies. I run this carb on a street port 12a, 3mm seals and RB header with a long primary system. I was wondering if Im going to be running lean at high RPM's with my stock fuel pump. I pulls extremely hard up to 8k and I not willing to go much past that. Do you guys think im running lean at that level. I checked my plugs and it seems to be a healthy burn.

 

did you put larger carb jets when you enlarged your venturies??

usally if the fuel pump is too small around 6 to 8 thousand rpms the motor will cut out, that means you emptied the float bowls ,, time to put a bigger pump!

 

A weak fuel pump will be more evident in the later gears as the engine's under more load and there's more time to suck the floats dry. If you try going flat out in 3rd or 4th the car will probably fall flat on it's face at higher rpm. Just judging by your setup though I'd say a decent fuel pump is a must.

 

A Carter pump and Holley Regulator is pretty inexpensive compared to the rest of the hardware, it seems like a no-brainer to me.