I have recently had my 454 rebuilt and dynoed by a local shop. I think the dyno #s are a little low and I would like some input please. The motor is a mark 4 454 bored .030 with stock stroke and rod length. Pistons are 23 cc SRP small domes. Claculated compression by the shop that put it together was 9.68. It has Brodix RR 270cc ovals and a hydraulic roller cam , .241 and .249 @ 50. Lift is 625 , 625 on a 110 and the lifters are Comp Cam short travel rollers. The intake is a Holley strip dominator with a Holley 850 street HP carb. It also has Hooker comp headers. It made 516hp and 529ftlbs all before 5400 and started dropping from there. Does this seem correct or do I have issues somewhere ?