Hello I need advice on what carb to purchase and what high rise intake to buy to beef up my 455. Also the best headers?

 

Some of this will really depend on how the 455 is built. In general the Olds 455 will run just fine with a 750 CFM carb. You can go bigger if you have the right combination of heads, cam, etc. The brand is up to you and whatever you are comfortable tuning. Some people stay true to the Quadrajets, other like Edlebrock and some like a Holley style carb. I like Holley only because I have years of experience tuning them but all are good and can be made to work. If you run an auto trans your best bet is a vacuum secondary carb.
As far as intake... the first question is hood clearence. The popular choice is Edlebrock performer intake which will let you run any carb including Quadrajets. It is not concidered a "high rise". It does fit under the hood in most cases and is a dual plan which is good for street performance. The other choices are the Performer RPM and Torker intakes. The Performer RPM is still a dual plan, but is higher and has the air gap feature... sort of the best of both worlds... good low end and can still produce power on the top end. The Torker is a single plan. I know some people like them but I personally lost to much low end performance when I tried one. Again it depends on what you are trying to gain and what the motor has been built for.
As far as headers... The biggest issue is finding a set that fit in the car you have. No matter what I have tried they all have needed to be modified a little. So far the best pair of headers I have used have been the Hooker Competition headers. These seem to fit best in 68 to 72 442's and cutlass models.