Originally Posted by Rapinator126
The limit for the 5.0 is 600-650. And a coyote with 430 will eat a 3v with 500.
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A 430 hp 5.0 will eat a 500 hp 4.6 really that does not make sense at all
sorry but here is a quote from a 5.0 owner.
Slagburn's car ( 5.0 ) was making about 500-520whp for over a year and something like 25K miles. He upped the boost and was making right at 560whp for iirc about 7k miles and is now building his motor thanks to an oh so slightly bent rod. He got lucky and cought it before it completely let go and put windows in the block. I believe he was shifting at 7K also. If you want a true to god reliable power limit I would say 525whp and you can enjoy the motor living for a long time like that. Once you go above that it starts to become a crap shoot.
Roush warrants their stuff at 3yr 36k at 575hp at the crank, I'd say that is what is reliable. Anything more than that and you are just reducing longevity. If you can't build a motor when the first one goes it's probably best not to go past that, it is really fun when you do though...
Ford will warranty a 525 S/C kit running 6 or so lbs. The don't warranty the 624 hp version which is 9 or so lbs. Those are flywheel ratings. I'd say Roush is pushing it with 575hp. Because this is a guessing game I'd say 550hp so 7 lbs of boost for be safe and get at least 75k miles out of your car. Yes you
can run 600 Hp but you are running on borrowed time.
So most 5.0s I've seen put down in the neighborhood of 365 stock or ~12% loss. At the end of the day it still doesn't matter. What matters is crank horsepower. Wheel horsepower is a false indicator because of how much variation can be seen in dyno numbers. At the end of the day I'm sticking with 575-650 crank horsepower and you should be enjoying your car without opening the motor for near factory longevity. It will still be critical to take actual use and proper maintenance in to consideration though.
Your exactly right, 12% is the norm. Auto cars used to be close to 20% but now they are becoming more and more efficient and I think they are around the 15% mark now. I would have completely agreed with your HP claim as well until my buddy's car bent a rod at right around 580whp. Granted it got A LOT of abuse and miles on it at around 520whp but still. I think at 600whp if you take care of it an otherwise un modded/abused car will probably make it 10K ish miles before it breaks but there are so many variables in this equation that no one can say for sure.
Concerning the 5.0.
You could run 650 whp and baby it and be fine. You could also run 550 whp and beat the christ out of it and pop your motor in a few thousand miles. All depends on what you want to do with it. If you have a lead foot as most do
500 Hp would be my absolute MAX as I want to drive my mustang more than 10 k miles wihout having to rebuild my 5.0 not cheap.
People tend to forget about all of the non-motor, ancillary items too. Driveshaft, half shafts, rear end, clutch etc. - they'll all suffer under increased power. It's worth it to take your time to do it right rather than slap a supercharger on there to make crazy power and then have a time bomb that's breaking down every few thousand miles for some reason or another.
So in conclusion the 5.0 just like any motor has safe limits just like the 4.6.
You want to run 600RWHP good luck it won't hold.