We have used 36 deg. of timing on our 521, and 32-34 deg. of timing with our 557. Engine systems has told us that with the 592 that we are building we should use no more than 29 deg. The reason is that they found anywhere from 20 to 35 more horsepower by taking their timing from 34 to 29. Has anyone else saw these kind of results? Note; this information is with the use of A-heads.