i do not think that rigth on the cam that is the rpm band on the cam . a cam for lets say a 454 to 468 will run different in a 396 smaller engine etc .but it will idle be low 1000 rpms unless you have a cam from hell big lift over 600 and 260 @0.50 DURA ON 108 . about the donovan blocks they make nice stuff it is not cheap get on the web and look at it .IT IS $5000 FOR A BLOCK AND THEY NEED TO BE FINSH MACHINED