Part Peformance

[1969Mach1]

Sorry but I'm kinda new and I just wanna learn some more about my engine and performance parts. I know the basics of engines but I don't know what is worth changing right now. Also I don't really even know what has been done to my engine. When I pull it out I hope to find out what's been done to it.
I was looking to add abit more power to my engine. Right now I have a chance to buy a Edelbrock PERFORMER 351-W (IDLE-5500 RPM) Intake Manifold for my 351-4bbl. I was wondering how much hp will it give me, I have a Holly Carb I think the 600cfm on it but not 100% sure. Also a K&N Air Filter if that makes a difference. I can pick it up for $150 Canadian (apx $95 US) it's used but in good condition.

Also next question should I change my ignition coil (I don't believe there is anything special with the one I got now) also which brand do you suggest. Also should I change my ignition, and which one too. What performance difference will I notice with changing each of these.

Thank you for your patience and helping me out. I figured if there was anyone best to ask it was you guys.

Thanks!
§am.