How much vacuum are you pulling at idle?

October 11, 2011, 06:31:40 PM

Hey guys. I have recently completed a 5.0 engine build and swap into my TurboCoupe. But the car seems to be down on power as compared to my Mustang. So I was just tinkering to check the normal healthy motor diagnostics...

I pulled the plugs to see if there was any indication of a problem in the combustion chambers:

I then hooked up my vacuum gauge and started the car. The gauge read 15-16 Hg at idle (~1000 rpm).

I then hooked up my vacuum gauge to the healthy Mustang 5.0 and started the car. The gauge read 19-20 Hg at idle (~1000 rpm).

The mustang is stock except for a K&N filter, 73mm MAF and a 3/8" Phenolic intake spacer. The thunderbird 5.0 is fairly stock except for GT40 heads and like intake spacer. Both cars have the stock HO cam.

What are you guys running for vacuum at idle? Please include your setup info.