1. You may not need a line bore. May just need a light line hone. May not need either. A good machine shop can check it for you.
The decks need to be squared up with the crank centerline. But, you may not need any extra cut off the decks. The less cut off, the better. It depends on the exact stroke of the crank, exact rod length, and exact piston pin height(compression distance). You can buy custom pistons with any pin height you want. This will allow you to get zero deck height, without cutting extra material off the decks. Auto Tec pistons are the cheapest customs I've found. Shannons Engineering is the cheapest Auto Tec dealer I've found. He must be a volume dealer. A guy at Auto Tec recommended him to me. There are also some Pontiac shops who can order 'em.
2. Don't have the engine bored 'til you choose a piston. Have the machine shop tell you what is the smallest bore size that your block will clean up. Then chose a piston in the smallest bore size that will work, based on the numbers the machine shop gives you. With custom pistons you can usually get them in most any size, in .005 increments. The cheapest Auto Tec customs are made from what they call shelf blanks. They usually stock these in most of the popular sizes, then machine them for whatever engine & specs needed. But, if they don't have a shelf blank in the exact size you need, they can make a new set from scratch. They'll just cost more.
As for rings, I always just used pre-fit TRW moly rings. But, many today recommend file-fit rings, so that the engine builder can file 'em for an exact ring gap. Of course, this is extra cost labor. Total Seal brand rings are popular. DON"T buy gapless rings. The most common ring size is 1/16" top & 2nd rings with 3/16" oil rings.
3. Porting not needed. Probably not worth the expense, for most street guys.
4. I always just used common TRW bearings, without any problems. But, some swear by certain brands & particular types. I'd ask some Pontiac engine builders for their opinion.
5. Voodoo - Hydraulic Flat Tappet - Lunati Power
Voodoo - Hydraulic Roller - Lunati Power
Don't need lifter bore braces with small HR cams. But won't hurt anything either.
6. Most reviews of the one piece seal have been good. But, as said, some prefer the Best Gasket rope.
7. I ran with a hole in that plug, and at least 70psi oil pressure, in my 455 bracket engines. Never had a problem. But, as mentioned, some prefer the 60psi pressure of the M54DS oil pump. I added some shims under the pressure spring, too increase pressure. Some say the larger 3.25" mains of the 455 block need a little more pressure than the smaller 3" main blocks. Opinions differ. Some say it all depends on the bearing clearances.
8. The M54DS is the most popular pump. Some say you should take 'em apart & clean 'em up real good. Butler sells a pump which they have modified, and has a thick bottom plate. You can buy a thick bottom plate from them & other sources. Some have reported leaks with the thin stock plates. Some put 2 stock plates on 'em.
9. Well known Pontiac racer, engine builder, & Q-jet expert, Cliff Ruggles, uses & recommends the Melling stock replacement timing set. The chains are plenty strong. And any chain, including the high dollar true roller chains will stretch almost as soon as the engine is broke in. After discovering this, many years ago, I switched to the TRW replacement set. No problems ever.
The Cloyes brand replacement set is a #C3007k
. They're about $25, from an Amazon seller.
10. It's a good idea to permanently plug the exhaust heat riser holes in the '67 intake. Otherwise you MUST run a stainless steel separator plate, & the correct gasket set-up. Pontiac had lots of problems with this set-up & discontinued it after only 1 year. Much easier to just block 'em off & run the later type gaskets.
Nothin wrong with the stock type points ignition system. I ran it in all my drag cars back in the 20th century. But, if you want later technology, while keeping the factory look, you can get the Pertronix points conversion set-up.