Originally Posted by fast68plymouth
Quote
Set it up temporarily with rubber hoses, so you can tune it easier


For sure

Russ, when you dynoed your 505, what was the power difference between the Holley SD and the 6bbl?


About 20 hp maybe a bit more at peak in favor of the SD.

6 pack ahead until about 3600. About a tie 3600 to 4300, SD after that to 6000.

Average about 10 hp difference.

SD had a 1" open phenolic spacer, and I worked a little harder (more jet changes/more pulls) on it than the 6 pack.