434 in a stock block with 6 inch rods..and NO BLOCK FILLER EVER!!!..metal must expand when it gets hot, if you fill the block that is where split cylinders come from car runs 5.70s with 1.21 and 1.22 60fts and weighs 2880 with me in it and has 7 years of running on the block and have had many engines and block last alot longer than that...don't believe all the internet hype