On my 81 trans am here is carb # 17081285 and 1261dkj cant seem to find any info on it any help would be great.
That is partially correct. What actually happens is that the secondary air door is only drawn open as far as the airflow dictates. Its on a light spring, so if you put the same carb on a 305 and a 454, the 454 will draw that door open much farther.Jmark said:That carb has the potential to flow 750cfm. It's probably lower since the engine size is small. GM sets the top butterfly max opening to control the cfm of the carb according to the engine size.