I am trying to find some information on big block Vortec heads. I want to put them on an 81 454 block. I am looking for about 500 horse, and want to know if these heads will support that. I want to run a Lunati voodoo cam with an RPM range of 2000-5500 with a max lift of .544 on the valve with 1.7 rockers. Does the Vortec have a 1.7 rocker stock? Will the head handle those numbers stock? I am having a hard time finding much information on the heads, and the information I have found is inconsistent. I would like to find someone who has ran these heads to see what kind of numbers they are running. I would also like to know if I should port the heads or if it is not worth for the numbers I will be running. Basically any help would be appreciated. The head casting numbers are 10141279. Thanks a lot!