I have a 65 289 block with 66 289 heads. The deck height is still stock and the heads haven't been shaved. What i need to know is how big is the max cam lift for this engine.
I would find specs on the HiPo cam and the LeMans cam sold back in the day and not exceed those numbers. That would be safe. You will, however, need screw-in studs and more spring if you go to a higher lift cam. Still check p-v clearance if you install a new cam.
I believe you can run up to about .550 lift. I know on the 5.0's, they can run up to a .540 lift. The cam in my car is at .445 (Isky 262 Super). Hope this helps.
Uh, the above advice from Z06... should not be taken if you have stock-spec 66 heads from an A or C code motor. You haven't stated otherwise, so I have assumed that you do not already have screw-in studs, deepened spring pockets and a spring upgrade - all of which, I think, would be required for a .550" lift cam.
I was just looking at different cams online and none of them said anything about engine modifications even at .570 lift. I was soley taking into account valve clearance and not condition of the heads. I know a guy running Windsor Jr's on a 289 with a .520 cam in it with no custom pistons.
The cam company will be very helpful if you call their tech line, but their on-line stuff won't say much because there are just too many variables. The issues will be spring bind at some lift, spring rate and piston clearance. Not all spring/valve combos can handle high lift, esp. factory stuff designed to work with low-lift cams. It's one thing to arm-chair these things, but another to put together a motor without doing the homework and find that the motor grenades from bent/broken valves or pistons. I grenaded a piston back in the 60's and learned that lesson the hard way.