My engine combo is in the 9 seconds tread. I know that race blocks are better, safer and make more power. But my conventional headed, stock LA block, low compression engine will push 2930 lbs 5.85 in the 8th and 9.35 in the 1/4 and when we had it apart it showed no signs of cap walk or any other problems. I do have a R3 block for when I step it up. But to be honest 142 mph is about as fast as I want to go. I'm just a braket racer and a 6.00 index racer.