I have only had a world products alumnium block, It has Edelbrock Victor JR. heads. race in Nostalgia Super Stock, makes 720 HP Only things I did in prep was hone the lifter bores, and bore to fit my pistons. been using it for 7 years, freshened once and it looked like new when I took it apart. Best investemnt I ever made for my race car. I cracked a stock iron block on average every two years. Never blew one up, but always found cracks on rebuilding.