Hello posting this for my father.

He has a 440 that was running just fine and then he swapped out the heads for a set of Stealth cnc ported version 440 source heads.

The heads were the only things changed on the motor and ever since then the motor has popped out of the exhaust on both sides of the motor. He started replacing everything he could think of: all ignition parts including dist., both carbs(dual 4 setup), fuel pump, head gaskets, intake gaskets.

Timing is 12 initial with 36 total.

Compression test was 190 +/- 10 in all cylinders. Sorry no access to a leak down tester. He did notice a sticking number 8 exhaust valve while running through lash and fixed that with honing the valve guide out to proper clearance. None of the other valves were tight. Adjusted the lash tighter and than really loose but it made no difference. No flattened or wore down lobes.

He is out of ideas as am I. He is sending the heads off Monday to get vacuum tested.

Any help would be appreciated. thank you