Intake Manifold Sealing Problem
Around here we have Autozone stores which rent cooling system pressure testers -- actually they don't charge, just a deposit.
Very nice -- you remove the radiator cap and attach the gauge and pump. Pump the cooling system to 13 psi and if you have leaks... it comes out the leaky area. Makes it quick to diagnose.
1970 Cougar, 3660 lbs
418W, C6, 3.50 posi, slicks & street trim
Best 1/4 mi: 11.24 @ 119 MPH Best 1/8 mi: 7.13 @ 96.32MPH