any body heard good /bad about these new blocks. I called world and they wanted 3400 finish machined for a 4.50 bore, but Mancini was 2650 finish machined. How can there be that much difference between world ( who makes them ) and Mancini?? World says the can easily take 1000 horse and probably 1500. I have dealt with mancini in the past and liked them, had no problems. neal zimmerman, eugene oregon