I need advice I purchase my 2nd jet boat it's a 1978 nordic mini day it has a 460 ford and a 12jg-a berk. I bought the boat from the original owner, and made a bad purchase I paid to much for the boat and now every trip out is a epic fail.
I brought the boat home from mo with out water testing it the original owner was 93 so I took his word that it ran good. Upon bringing it home we rebuilt the carb and added a edelbrock performer 460 manifold, place diverter, recabled the entire boat, added a gas pedal, changed oil, greased and fixed wiring, removed old carpet.

First water test oil started bubbling out between head and intake, water in oil, found blown intake gasket right bank. I figured I purchased the wrong  gaskets cause there was no hole in the middle for the cross over port. Well new gaskets came and we installed them the middle cross over port is now blocked by the gasket and the rear water ports can't flow thru the manifold cause there is no port.

2nd water test when secondaries open motor would die if you din't let of the gas installed fuel presure gauge presure at 5psi wide open was adjusting rear float and boat started on fire. Lucky  fire extingusure and bucket handy! Retired burn't harness and replaced melted hoses.

3rd water test boat  still would die when 4 barrels opened removed rear float bowl found rubber in bowl. Replace all fuel lines and filter tanks are aluminum and clean.

4th water test boat ran good 53 on GPS 4800rpm tied to dock came out next morning and boat had sank. Lucky it was shallow. Re floated boat towed to trailer found gasket on transom rotted out. Replaced gasket and installed auto bilge pump, changed oil, oil filter and battery.

5th time out boat running good then when letting of gas it would stall found lots of steam coming out of breather. Checked oil and white pulled to trailer (FRUSTRATED)!

My cooling system is piped from jet to a "t" no gate valve then from the "t" one hose to the front bottom of each manifold (log style thru transome.) then from the front top of the manifold to the water pump block off plate, then out the housing on the front of the intake manifold to the back of the "p" trap.

I need to know how to figure out how the water is getting in the oil, how to pipe the cooling system if its not right and if this is the right intake manifold for the boat even though it only has one cooling passage.