I know its not a truck but its still the same motor basically,... long story short, my boat originally had a 302 and the block cracked last year so i found a used 351w truck motor in my budget and put that in.. the motor starts and runs well but has no compression (under 20 pounds) on the left bank (right bank is good). Is there a way to check and see if it is an intake, head gasket, heads, or piston rings?? It also was leaking water into the cylinders but this may or may not be due to the original 75 marine exhaust.

 

leak down test..