Right now I am able to sustain 3800 rpm for 30min on a 19' jet with AA impeller. I am rebuilding the engine with all forged bottom end. Other than piston to cylinder and valve guide differences for marine engine, what else do I need so I can sustain 5000rpm for about 15min.

Enough oil and fast enough oil drain back. Unless you have an Olds this won't be a problem.

A Ford modular motor is designed to run at high RPM/Loads for extended periods of time. The V10s run at 4500 in UHaul trucks for most of their lives. As long as air/fuel is correct an engine should be able to run for hours at max RPM/load. That is one of the tests engineers do long before they ever install a new engine design in a car.

Its a 4.6 DOHC all aluminum Ford mod motor. It'll push over 5k now, but I don't trust the stock bottom end w/too much boost. My oil pressure stays about 75psi at 3800 for the whole time and when changed looks good. Running 10qt pan. Great drain back on these engines. A/F ratio is 11:1-11.5:1 under boost and has a Walbro 225liter fuel pump. Never runs out of fuel. I just wanted to know if there was anything special other than piston-cylinder and valve guide clearance that needed to be done to run higher rpms for longer periods of time.

The list is endless.

Oil temperature control is probably key.

The easiest way to accomplish this is to install an oil cooler.  I may get hammered for this but run the dump line to the cooler. Keeping the oil temp between 210°F and 250°F. The 140°F or so water temp is perfect for this task.

Piston to wall clearance is material specific and would require a bit of research. Personally I would rather see the engine temp warmed up.  (Consistently, not with one of those spring loaded bypass deals). I would also recommend using an automotive style block mounted water pump.

Something else to consider is valve stem clearance.

This thing sounds fun!

GT

The list is endless.

Oil temperature control is probably key.

The easiest way to accomplish this is to install an oil cooler.  I may get hammered for this but run the dump line to the cooler. Keeping the oil temp between 210°F and 250°F. The 140°F or so water temp is perfect for this task.

Piston to wall clearance is material specific and would require a bit of research. Personally I would rather see the engine temp warmed up.  (Consistently, not with one of those spring loaded bypass deals). I would also recommend using an automotive style block mounted water pump.

Something else to consider is valve stem clearance.

This thing sounds fun!

GT

I've always wondered about putting a cooler on the dump side. Always figured the lake water would cool too much. When I do my cooler its goin on the dump side 👍


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I've also thought about running it on a valve like my headers are setup so one it gets hot I can regulate temp from the seat. It already takes an eternity to get the oil to temp without a cooler


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This is why I do it this way. The warm water heats the oil above 140° F  really quickly.

GT

So what heat exchanger would you guys recommend? I'm running a turbo with 10qt pan and will be pushing 700hp.

Are you running a remote oil filter?

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Yes, I run a remote oil filter.