Hi, this is my first time to the forum, lots of good information here. But anyways, Ive got a 70's FE 390, its in a 75 ford f100. The 390 has been bored .040", 10.0:1 pistons, and a highlift cam (i dont know the exact specs cause my dad can't find the papers, but supposively its got .50" lift), the motor also has electronic duraspark ignition and a Holley 4150 650cfm carb.

The problem is that there is some serious engine blow-by, the oil is blown right out of the engine breather tube at the back of the intake and then none is left, and thats just going a couple of miles down the road and back.

I've taken the rocker covers off, and discovered a bent pushrod on the #1 cylinder intake side, so we replaced it and installed new intake gaskets, (didnt help). So now ive just done a compression test, cylinders #6,7,8 have compression that is excessively low, as follows, 90, 50, 70 psi, which is low considering the highest in the engine is 150-160 psi! I believe its head gasket, but it might also be the valves. If anyone has heard of this happening, any help would be appriciated. Thanks