how much a cast iron crank can hold?

Hi, I have a 4.3 cast iron crank with 6.605 forged steel H-beam rods, how much power(hp) do you think this combo can hold?
This came with a 521 BBF bought from ford performance parts, and Im going to change to JE pistons to make it a 547 with 14:1 compression with alcohol fuel injection

My last engine had cast crank with a 671 on it. Made about 750 hp. (9.4 @145mph 3600#)
Had rev limiter at 7000.
Have heard lot higher hp but it all comes down to how well it is built I guess.
I'm sure others will have more experience.

frankcons87 wrote:Hi, I have a 4.3 cast iron crank with 6.605 forged steel H-beam rods, how much power(hp) do you think this combo can hold?
This came with a 521 BBF bought from ford performance parts, and Im going to change to JE pistons to make it a 547 with 14:1 compression with alcohol fuel injection

Yours is kind of a loaded question but if you have the Ford Racing crank & rods then it’s a Scat cast steel crank with 2.50” rod journals and Eagle H-beam rods.  In a naturally aspirated alcohol engine as your describe, that particular crank & rod combo ought to hold as much power as you can subject it, meaning 1000 HP N/A on alcohol is not entirely unrealistic.  As with most any internal engine component the more power to which it is subjected the shorter the service life, but unless you’re always making 800-1000 HP non-stop consistently down the track those items could last many many years.

If you have a brown box crank of similar dimensions, then this answer does not necessarily apply.

The stock factory iron cranks are very very strong. But at the stock stroke, they have more "meat" or overlap between the main journals and the crank throws or connecting rod journals.
The more stroke the crank has, the less overlap between these areas.

The cast steel crank will do a fine job like Paul said . Keep the rpm "around " 7,000 you shouldn't have any problems.