you may also run into problems with the rocker towers (i think this is what they are called), when i did my 5k with a 30/70 cam i had to have these machined down to stop the push rods making noise. Also a thought to machine the hydrolic lifters when you do the cam, unless you are planning solid lifters. I used crow cam dbl springs from a torana for mine and they work fine. Got the head ported and polished and massive valves put in and my 5k is good for 7500 without missing a beat. never pushed it harder but it would go i recon. anyway that's my two bobs,
cheers