Merc 350 Mag gurus? Help plz
 

Serious problem with old 350 Merc mag. Oil is milky, runs like chit.. seems like it's running on 2-3 cyl. not all 8. Can't get above 1800 RPM. sputers, rough etc. etc. Water in the cylinders, I'm sure. Gill headers. Probably leaked. So my problem?
Fixable? chit can the motor? If the Gill headers leak, can they be fixed?
No compression on 2 cylinders, aout 60 on one. 170+- on the rest.
What should I do? Rings. or just chit can the motor.
Doubt it's worth fixing. Anyone has a good used 454 Mag. Circa. 1994-5 ? and bravo drives?

THx
p

350 mag
 

if you go to screamandfly.com and check the for sale IO engine section guy has a fresh 350 vortec long block for like 1200$