I saw this old post and I thought I'd update it just for fun. It would rev up to 7K fast with no problems, but I was only at 1000'. The block was a 400 block I had sonic tested and passed, it had a Hughes girdle and billet steel caps but a bore still cracked after very few runs (after driving 13 hours to the ET Finals no less). So I got another block and half filled it this time and went to a Bullet 277@ .050 .640 lift cam and everything else the same. T&D 1.5 rockers. It was 60 footing 1.28's and was making it almost to the end but I still didn't want to rev it that high. Best ET was 9.77 at 134.60. Keep in mind the air here is very good, in the spring and fall it can go down to -126 feet D.A. It was a bit of an animal with the 4.56's so I went to 4.10's. 60' slowed to a 1.30 but with a new best of 9.62 at 136.6! Then in late 2019 I managed to get my hands on a new Callies 440 block. I tried to sell the low deck complete carb to pan and start over but it had a high price tag because it was all fresh so I didn't find a buyer. I ended up selling just the bare short block so I could reuse mostly everything except the intake on the new RB block. Built the RB pretty much the same, Molnar crank, Molnar Chevy rods, ICON pistons 512cu in. (4.375"x 4.25") I was going to try and get it in the car for the last couple of races but I got the heads on before I realized how far off the new intake ports were and I ran out of time. The new block is upwards of 100lbs heavier so I expect it will run a bit slower but I'll update again when I run it. Thanks for the replies and advice.