[MidOHasp]

You mentioned forged steel, but didnt mention if, and from whom, they are available.

IMHO, and I'm not currently trying to do a budget FE build (or any build for that matter), the $430 for a new cast iron crank from a reputable place like SCAT might be money well spent. Although %age wise, that depends on what your total budget is...

I wouldn't attach H-Beam rods and Forged Pistons, by the way, to a 40-year old cast iron crank. Just doesn't make sense. Chain's as strong as its weakest link.

At that rate, put in some good upper-mid-grade I-Beams and some "good" pistons and just see what you can do with it and have some fun.

550HP is gonna be a stretch, man...you're going to have to do it with RPM, compression, etc... on a solid flat tappet cam like that.