You may find that you can cast as far with 2.75lb TC rods as you can with 3.25lb; it is very much down to technique, and being able to generate the tip speed on the cast.
For example, bank to bank at Wick lane dam is around 125metres, I could cast that with 2.75lb TC rods, 15lb line Aerlex 8000's and 3oz leads.
To get the best out of my 3.25lb TC's I have to go up to 3.5oz leads.
The rod itself, you are not going to cast as far with a cheap budget blank as a more expensive better built rod, with better materials, despite what the lovely manufacturers tell you. The technology and materials of my Century SP's is better than the materials of my Rod Hutchinson The Ones, and The Ones do not add much more distance, as much as I practise casting.
When I get to cast out I physically go through my casting action, like a golfers practise swing. I check my feet, hand positions, even the swing. I also have a practise cast to wet the line and the rings.
Long distance casting in snag free waters mean you can use a shock leader, and to be honest, fine your line down. If you don't need 15lb line, and can safely drop to 12 or 10lb then do so. Before anyone calls me irresponsible, bear in mind, in water basically your line will take 4 times its breaking strain, so 40lb on 10lb, and playing a fish safely, carefully, you can land bigger than that.
Ballistics:
Lead shapes, look at bullets, shells, for rifles, tapering down from a point, so go to tournament leads, they do get best distance with pears not far behind.
The angle that you cast at is the angle the lead hits the water, and 45degrees is the angle at which you gain most distance, obviously wind and feathering down will have an effect on that.
Keep your rigs tidy, as short as possible. I still prefer to use run rings, rather than helicopter leads, although I do know that sacrifices a few metres, but helicopter set-ups I have found give funny takes, and using that heli set-up, you will need a shockleader as the lead and rig do frag the line. (Incidentally it is that fragging the line that was the reason for leadcore, not its supposed sinking).
Inline leads, because of the swivel or rig coming out the front wobble in flight.
Give your cast everything you can, don't hold back, holding back will cost you distance.