I am building a 466. I plan on putting this in a 1977 f-150 4x4 long bed, it has 38 in boggers, 5.13 gears. I plan on making about 600-700 horse if possible. I am going to use a scat 9000 series crank 3.85 stroke, kb +3 flat top 2 valve relief, eagle H beam rods 6.605, Edelbrock cj rpm or victor heads, full roller rockers, 850 holley center squarter carb, msd ignition, haven't decided on intake or cam. I will be mostly bogging this in compitition, but it still has to be streetable. I have restriction on how much vacuum I can run on my motor for my class. I have to pull 10 lbs. of vacuum at 1000 rpm. I am also going to have the bottom end balanced. So, I guess my questions are, what size cam i can run, and what harmonic balancer and flexplate should i use and do i need a spacer?