"...I want it to be a fun street bruiser that could knock off mid 12's and look good punishing some 295 radials..."
The easiest way to meet your goal is with a long stroke engine. As long as your block's casting number does not end with 557, it can be used for the stroker build. Butler sells balanced cast crank stroker assemblies for about $1600-$1700 shipped.
Butler Performance - Pontiac Engine & Rotating Assembly Combinations - Featuring Eagle Pontiac Kits
There are crank, piston, and rod upgrades available at extra cost.
OR, you may come out better buying a stroker shortblock, or complete crate longblock, from one of the Pontiac engine builders. One of the the cheapest good quality shortblocks I know of is from Len Williams. He can also build 'em with any upgrades you want, in both short and long block.
455 Short Block
455 Long Block
Sandoval has the shortblocks for about the same price.
pontiac crate engines
6x-8 heads will work, are cheaper, and likely won't need new seats, like the early heads will. Also won't need dish pistons, with the 6x heads. But, since you are considering alum heads & a roller cam, I assume you have enuff $$ for a nice engine build, and don't care about having any of the "correct" numbered parts, so I'd go with 85cc KRE alum D-port heads, & a small hyd roller cam, with some decent alum roller rockers.
Kauffman Racing Equipment
Kauffman Racing Equipment
Butler Performance - Pontiac Camshafts
Harland Sharp Original Roller Rockers S6001 - Free Shipping on Orders Over $99 at Summit Racing
Scorpion Endurance Series Rocker Arms 3052 - Free Shipping on Orders Over $99 at Summit Racing
If you wanna save a few hundred bucks, most any of the 041 grind HFT cams, with Rhoads lifters, will produce the power you want. There are also lots of other HFT cams that will work. But if you don't use Rhoads lifters, most recommend only the Hylift-Johnson 951R lifters. The Rhoads are modified Hylift-Johnsons.
Paul Knippen is a Pontiac engine builder who sells the Hylift-Johnsons.
Two of the most popular versions of the 041 grind are the Crower 60919, and the Melling SPC-8. The Melling is cheaper. I used several of these in some of our bracket cars.
Engine Camshaft Stock Melling SPC 8 Fits 68 70 Pontiac Firebird 6 6L V8 | eBay
Rhoads Original Hydraulic Flat Tappet Lifters 9518 - Free Shipping on Orders Over $99 at Summit Racing
I'm a carb guy. I know absolutely nothing about a fuel injection deal for a Pontiac, so I won't say any more about it. We always ran 750 Q-jets on our 12 sec bracket engines.
PS: Keep in mind that when you increase the hp/torque that much, the stock 8.2" rear end may not be up to the task, if you get any traction. I'd consider upgrading to a 12-bolt rear, or at least an 8.5" 10-bolt. We ran stock 12-bolts and never broke any part of one, running down into the high 11's, with big slicks--TH400/455/3.55-4.11 gears. But, a new, complete 12-bolt is about $3000 or more.
Pinion head may be able to fix you up with something a little cheaper. ?