72 L24 Engine Rebuild

I am restoring a 72 240. The car is very tired, so I plan on pulling the engine, and going through it. The original engine output is not enough for me, however I do want to be able to drive the car on the street with the A/C on when finished. I picked up some parts for the rebuild/ upgrade already. I have a new cam, and rockers. I think the cam is 260 degrees duration. I don't remember the lift offhand, but fairly mild. I picked an electronic distributer ( the one with the internal electronics from a later model Z), headers, and I plan on 2, or 2 1/2" exhaust ( sugestions?). I will send the original carbs to z therapy for a total rebuild, again any ideas on carb setup would be helpful.

I am thinking about adding an E-31 head. I need to have machine work done on my present head, and I see these around for under $200.00. Is it a worthwhile adder? I have also seen an E-33 manifold which it's owner said was superior to the E-88 I now have as it had larger passages, again it was only 40 bucks, should I add it to the package?

How about pistons? Dish, flat top, or ? Keeping in mind preium gas is the best I can get . I also see alum. flywheels around they seem to bring about 250 bucks. Any ideas on these?

One non engine change I am thinking of is adding a R180 4:11 rearend, and five speed transmission. I read a post where someone highly recommended this change. They stated the final drive ratio was higher with this setup, than the original four speed.

Any ideas on this would be greatly appreciated. This is my first , and I want the car to be able to get on and off the freeway quickly.