saccyclone
Active Member
1969 440 stock cam, stock intake and exhaust manifold, holly 850 vacuum secondary.
Alright....i took three different vacuum gauges out to the car this am and came up with the following numbers:
At idle: 20in first gauge / 21in second gauge / 19in third gauge
At 2000 rpm: 21.5in / 23in / 20.5
From 2000rpm quick release back to idle the highest number attained: 23.5 / 25 / 21
During the quick release, the needle sweep from highest back to 20in was smooth and steady and only took about 2 seconds. It was not instant.
So, the good part is that i never went above 25in of vacuum but these numbers still seem high. Still could be a back pressure issue with heat riser, muffler or???
Alright....i took three different vacuum gauges out to the car this am and came up with the following numbers:
At idle: 20in first gauge / 21in second gauge / 19in third gauge
At 2000 rpm: 21.5in / 23in / 20.5
From 2000rpm quick release back to idle the highest number attained: 23.5 / 25 / 21
During the quick release, the needle sweep from highest back to 20in was smooth and steady and only took about 2 seconds. It was not instant.
So, the good part is that i never went above 25in of vacuum but these numbers still seem high. Still could be a back pressure issue with heat riser, muffler or???
