Id like to add the following .....
Factory performance parts are actually pretty darn good for two reasons. The same reasons that are still true today. The factory makes a part the performs and lasts. It performs to meet the goal of the car and lasts because they have to warranty the part should it fail. And that becomes very expensive quickly.
From top to bottom on the engine;
Air cleaners;
The factory HP air cleaners are pretty efficient and often a good looking part on top of it.
Carb's;
While we have a few members that just scream one word, "Holley," understand that the factory Carter carbs do indeed have enough behind them to power your engine. While there not as flexable and super tune able as that nice $400+ Holley that still requires a jet kit or that wonderful $800 custom, Holley based carb, think if you could use that money else where more wisely?
My favorite carb is the junk yard or swap meet steal. Rebuild them and the total price is a fraction of the cost of a new base model carb. Get to know your carb numbers and styles and know what they flow from wise.
I get a ton of flak from some members on the use of the TQ carb. I look at it this way. For street and mild HP builds, a $50 core, $50 rebuild kit and I have a carb flowing over 700cfm that is flexable enough to street/strip it. Run 11's or use on a street and get 20mpg's?
I'm sorry, but spend $800 for what again? I'm not racing for the money people.
Intake manifold;
Sure it is heavy as heck. Save half the weight by spending $230+ for how much gain in power? It has been said over and over here and in print, it's NOT a bad part. It is 400hp capable.
Next up is a subject of great debate.
Heads;
Even with the small valve sizes that came in the low compression/smog years, the iron heads can be rebuilt with the larger valves IF you really need them and in many cases, you don't. A key component to making power is air flow and much can be gained in the heads. Even smog year factory small valve heads can be rebuilt and given a bowl porting to flow enough air to make over 450 HP. And guess what!?!?! There's still room to expand on!
The other thing is the can be redone for less than those new aluminum units your eye balling. In which once you get them, they still very well may need work out of the box. Heck, just checking them is an added cost you didn't think about did you?
A lot of people purchase these aluminum heads and do not take advantage of there breathing capability.
Why are you spending more for heads and not taking advantage? To save 50lbs.?
LMAO!!!!
The camshaft;
Read up on the manufacturers site. They often explain cams at a hot riders level, not a rocket scientist level. This is so you can make a choice. An informed choice. If all else fails, you can call them. They will even custom grind you a cam for chump change over the off the shelf cam price.
Hey! It's your money, use it wisely, you worked hard for it, and as one member says, pick your parts spend your money.
The best advise I can give to the general public is to simply "Make a plan and stick to it because changing plans cost a lot of money." Also remember, there is no shame in doing a copy cat build. Hell! Just thank the guy that did the build first. That person just saved you a lot of time and money and your copy caring is seriously just a compliment to them. There are a lot of builds out there.