Take everything you know about chevy's and set it aside. Not much of it applies in this world. Pontiacs make mountains of torque and it's there "right now" from just above idle. They don't need much gear or a super loose converter. It's unusual to see a Pontiac street motor that turns more than 6000 rpm, or needs to. 5500 is "the norm".
First, how are you going to use the car? (street, street/strip, race only, highway cruiser, etc.)
What kind of fuel are you planning on running?
Which heads will you be using? (date code and casting code)
(Here's a reference: Cylinder Heads
) and have you cc'ed them yourself?
Also, which block (4 character date code on top rear near distributor hole, casting number on rear pad behind passenger side deck, and finally - 2 character code on passenger side front just below the deck)
750 cfm isn't enough for a serious Pontiac
That Edelbrock intake won't make as much power as your factory iron intake will.
That Lunati Bracket Master is a pretty mild cam in a 455. If you plan on running iron heads and pump gas, it's nowhere near enough cam to keep you out of detonation trouble at 9.8:1
cast vs. forged crank: Forged is a waste unless you're making north of 600-650 hp and/or regularly spinning the motor past 6500 rpm, and the rest of your combination isn't going to get you anywhere near either one of those figures. Forged H-beam rods are ALWAYS a good idea.
'Ram Air IV" manfolds only fit Edelbrock roundport heads and Pontiac factory round port heads (Ram Air IV, 68 1/2 Ram Air II, 71+ 455 HO, 73/4 455 SD)
And, the question I probably should have asked first --- what kind of budget are you working with?
I love talking about this stuff (and welcome) --- I'll be happy to share how I built my 461 and can also put you in touch with one of the best Pontiac engine guys there is. Here's his web site:
Central Virginia Machine Service - Home of the Injun Engine!
... and unlike many, if you consult with him he'll share honest information with you without making you spend money first.