fantomrush
+1y
Theres your problem. Start looking for another motor. If you have 0 compression in 3 and only 60 in the last the block is screwed. There is a major problem somewhere and Id put money on something being cracked or you some how bent a lot of valves. If timing is on like you said it is I dont see you bending any valves especially since these motors are noninterface. Im not 100% positive on the 2600 being noninterface. It could be a blown headgasket, but it would be blown so bad that it would leak oil and coolant from the head with 0 compression across the board.
Change the oil and let us know if you find anything in it... like coolant, water, metal, bearings, maybe a rod or piston.