Avenger 85- Low Power

The head torque on mine is set to 144 inch pounds.

I also have had bad experiences with acorn nuts, those were replaced with hex nuts a while back.

Do you have methods for testing for air leaks?
Yours is running at least. I haven't been able to get mine to run at all. When I'm checking an engine that doesn't run or is not installed, I use a "Mighty Vac" or a HF brake bleed pump connected with hose to the intake. You will need to make a plate or similar way to block exhaust off. This will show how much vacuum it holds (if any). To test pressure, I adjust the output on my air compressor to where its barely pushing any air, usually 3-5 psi, then I place the hose to the intake with the exhaust still blocked off. I then spray soapy water mix EVERYWHERE. Your leak should be quite easy to spot. I plan to make a slip on intake adaptor with a schrader valve so I can better control flow and pressure. Did you find your problem?