Yea, I was worried about it myself until I talked to THR and my tuner. They're not like your traditional cast iron crank, they're a nodular crank. The even look different than any cast crank I've ever seen. They can't handle the rpms a steel crank can handle though.

 

a stock GT block can hold 1500 hp, but for how long is the question... but basically anything up 1000 rwhp is is good

 

the connecting rods are the weak link. They are "legally" rated at 450hp. Depending on how much torque you have, depends on how much power it can hadle(hp is nothing but an equation of torque). Nitrous, I would say lower hp numbers, FI can handle higher hp numbers round 450rwhp, while the juice is aroun 400-420 ish. BUT to answer the op, 450hp is the legally rated max on the rods.

 

keep it at 400RWHP. some people have blown a motor with more or less. some have ran a motor with more or less. 400 is generally the safe zone.

 

The cobra crank can do 1500+ but as stated above the rods are bubble gum in Cobra's and GT's Except in the 03/04 cobra.

 

At power levels like that most are running at least a girdle though. They are strong, but not indestructable.

Its the internals that are weak. 450 is the absolute limit imo, anything above that and its only a matter of time before something lets loose. I have been on 420 whp for almost 2 years now with no problems.

 

I agree. Shaun Hyland said he builds 1400 hp motors with the stock block but does pull out all the bell and whistles to do it. Girdle and all. Our blocks have a really good main cap setup on them but anything can be broken.

 

If anyone has the money to build a 1000+ hp 4.6 and don't spend the extra 200 bucks on a girdle they need to be B slapped anyway. JMO

 

What's a girdle?

 

It bolts onto the main cap area, basically onto the bottom of the engine (bottom of engine inside oil pan area) and increases strength. Basically keeps the block from cracking or giving way.