Stock crank limit numbers?

RazerDev2014

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Sep 24, 2017
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So I've read everywhere that the stock internals will be teetering with death around 450hp, the only thing I'm wondering is the 450 to the crank or the wheels? I'm ordering a on3 kit at tax time and am unsure about the hp numbers I was thinking about running enough boost to hit 400 hp but if its dyno 400 then that means motor is making more power to the crank. Any help would be nice!
 
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a91what

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Typically the block takes a :poo: before the internals do, the mains 'twist' or 'walk' and cause the block to crack. A stock E7 headed 302 with a conservative tune at 15 psi will make 400hp and a mountain of torque.
The torque is what makes the car fun to drive HP is a great number if you are racing but on the street TQ is king for SOTP fun.
 

RazerDev2014

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Typically the block takes a :poo: before the internals do, the mains 'twist' or 'walk' and cause the block to crack. A stock E7 headed 302 with a conservative tune at 15 psi will make 400hp and a mountain of torque.
The torque is what makes the car fun to drive HP is a great number if you are racing but on the street TQ is king for SOTP fun.
Oh lol, I thought the romeo blocks were good for 1000+ horses
 

RazerDev2014

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Sorry I think you guys are confused lol, I have the pi 4.6l not a 5.0, what I've read says the rods are teetering with death at 450 horse. My question is if that's 450 to the wheels or 450 to the crank
 

a91what

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That's what I get for answering so late at night... lol.
I believe only the cobra got upgraded internals, from what I can find you will hit the break stuff wall around 400
 

Hoytster

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Oh lol, I thought the romeo blocks were good for 1000+ horses


You are correct, the Romeo iron blocks are usually good for 1000+ horses. The week link in the stock internals is the rods, that is what typically limits you to 400 RWHP with those engines. Even at that power level longevity is not guaranteed with the stock rods and pistons as the tune plays a major part in how these hold up.

EDIT: somehow I didn't see the last few responses, so just pay attention to the 400 RWHP part
 

silversmith82

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Ppl gotta stop recycling info they hear on the interwebs...

ANY 4.6L block is good for 4 figures. Iron, Teksid, WAP, Aluminator etc... The block is not the weak point, the rods are. Figure 400-500 or so and that depends on the tune and other factors.

The cast crank is not weak, if you break a cast crank you are either making HUGE power or you did something wrong. They are free, light and work well.

Great budget build is your stock block gone through, stock cast crank, $200 for boss rods and $550 for your choice of entry level forged piston. Good for 600rwhp no problem and you do not need more than that on a street car.
 

Hoytster

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Ppl gotta stop recycling info they hear on the interwebs...

ANY 4.6L block is good for 4 figures. Iron, Teksid, WAP, Aluminator etc... The block is not the weak point, the rods are. Figure 400-500 or so and that depends on the tune and other factors.

The cast crank is not weak, if you break a cast crank you are either making HUGE power or you did something wrong. They are free, light and work well.

Great budget build is your stock block gone through, stock cast crank, $200 for boss rods and $550 for your choice of entry level forged piston. Good for 600rwhp no problem and you do not need more than that on a street car.

Who recycled what info? I believe the OP was just loose with his terminology and meant to say the stock rotating assembly.
 

RazerDev2014

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Who recycled what info? I believe the OP was just loose with his terminology and meant to say the stock rotating assembly.
Yeah I was meaning the rotating assembly, I'm just curious as to what numbers on the dyno I'd be seeing, because say the rods go "bye bye" at 400hp (just using 400 as a base number here) then I should be seeing somewhere around 370-380 at the wheels, or would it be vice versa and I'd be seeing 400whp and the motor is actually making more power but the rwhp is the limiting factor. I plan on building the motor further next year to run more boost and get up to the 700-800hp range.
 

Hoytster

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....."The week link in the stock internals is the rods, that is what typically limits you to 400 RWHP with those engines."

So assuming ~15% drive train loss, you would be around 450-460HP at the crank. Again, these guidelines aren't like a light switch. Some motors have let go before the 400 RWHP mark while others have held up to much more. The tune plays a major role in this.
 

Dark04GT

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400-450rwhp is a good range - at that power level the tune and high revs (preventing them) will determine how the motor does. I‘m daily driving a 438rwhp GT- - good tune, good maintenance, and keeping it under 6k rpm will keep the motor going.
 
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