We ran one of them, a 557" engine one year, then went back to the 501" strokers, plenty of performance and they hang together very well!!! As Tech said, forget the stock heads!!!! We have one engine with some much reworked Edelbrock aluminum heads, and the other has a set of Ford Cobra Jet aluminum heads...both do a bit over 500 horse and torque at the wheels on the chassis dyno.

As for your Bronco, you didn't say what mods you have to the transmission and drivetrain, but the stroker motor will turn the stock parts to junk with all the extra torque!!!! 500+ ft lbs of torque due a lot of damage to driveline parts that are only rated for about 350 ft. lbs!!!!