Who makes the best engine????????

Who make the strongest and most relieble built engine, in the 4.6l and the 5.4l? I know I'm going to S/C it. I'm not sure which one of my 2 vehicles the motor will go in. I have a 2007 Roush stage 3 F150, and a 2008 Roush stage 3 Mustang.
I would like a motor to have 700-800 rwhp. I've thought about buying a GT500 motor and trans. One question I have? Is the internals forged? What's the max HP rating of a stock GT500 engine.
I was also wondering if the Navigator 5.4l 4V engine is fairly the same block and heads, minus the intake. as the GT500 motor? I know if I bought a navi motor, I would go all forged internals, and have heads ported and polished. and put a Kenne Bell S/C on it.
If this was your motor build which way would you go, to get atleast 700rwhp?
Buy a FRPP short or long block?
Buy a After market short or long block?
Just buy a GT500 engine?
Buy a navi engine, and rebuild it from the ground up?
Or just have a built 3V engine?

Only the Roush P-51 had forged internals. The stage 3 still has the factory block. I'm not sure, maybe someone can tell me? What is the difference in the heads from the navi to GT500 heads? I'm sure they didn't use the same heads on both motors. But could you get the navi heads ported and polished and rebuilt to the GT500 heads specs? Or would it be cheaper to just buy GT500 heads? I would suspect the blocks are the same on both motors, just different internals. But with ether motor I would have them rebuilt. Since I would be buying them used, and I like peace of mind knowing everything is right.
Another question, If I bought a complete GT500 motor with ECU and all wiring, what else would I need to buy, upgrade or change to be able to get the 700-800rwhp I'm looking for? From what all I've read, I would need. A different pulley,upgraded boost cooler and radiator, boost a pump or a second fuel pump, custom tuning, upgraded clutch. Would I need to get a different blower? Or can the factory S/C support that much HP?

Come on man some body gotta have an oppinion on the good, the bad, and the ugly. On some engine builders, like who to trust and who to stay away from. Do any of you guys have any personal experience with certain engine builders?

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