How much gain?

As you can probably tell this is my first engine rebuild. I'm kinda pissed that I have to do it in sections but I was wondering with what I'm able to do right now and maybe add different heads, intake, and carb later. Right now I'm changing to a performance cam & lifters from Edelbrock it's made for idle-5500 RPM and the timing gears as well. I was wondering by doing that along with removing the emissions controls and cat convertor how much horse & torque I might expect to gain. Hopefully I can get some Hedman headers soon as well and build myself a performance exhaust system running duals at 2 1/4" with a Magnaflow XL3 muffler. Also, how hard would it be to replace the intake while the engine is still in the car?

First don't just remove your emission controls because thats against the law! Instead get and underdrivepulley for your air pump and replace your cat with an aftermarket high flow one. Get two if you want duals! When you shop for your headers get ones with the air rails already on them. The intake is easy to remove while in the car! Just be carefull when removing the distibutor! You might consider getting a used engine that you can rebuild and still be able to drive your car. As far as your cam change drop the oil pan! The timing cover and oil pan seal to each other. If you don't drop the pan you'll never get the new seal in and you'll have a nasty oil leak!