With the parts you have; ie the 2600TC and 3.55s, and the 8/1 nominal Scr engine; plus depending on at what elevation you are at;
For a streeter; choosing a cam to keep your bottom-end torque, could be tricky.
And the next hurdle is that 5500 at the top of first with 26.5" tires comes to about, 43 mph. On the 1-2 shift,with a 904, the Rs fall to .59/ or 3250rpm. Too much cam and your 8/1 nominal smog 360 turns to mush, until the rpm picks up again. The higher your elevation the worse it gets.
On the street; power and performance may not necessarily be the same thing..... because
power is generally measured at some higher rpm, where you rarely drive at. As above, you get into second at 43 mph, and then 5500 doesn't come around again until 77 mph. With 3.55s, 65mph in second at WOT is gonna be about 4700. You don't need an XE274 to make power at 4700.
Now; if you just want to spin tires, that's another story.
But the XE274 is not gonna be happy with a 2600TC in your smog-engine, with 3.55s....... because to do that,you need POWER from stall to about where the cam starts working; not at 5500!
The XE274 power-peaks up near 5200. Which means the torque peak will be at or near 3700. So your engine is gonna have to make some power from Stall (2500 in your case), to somewhere near 3700, in and of itself, until the cam wakes up. Well, 3700 is gonna be around 26mph at WOT in first gear. That's a long wait in my book.
For bottom-end power;
The fastest, probably cheapest way, for off the line power, is a hi-stall. It does nothing for power, but because the engine is allowed to spool up to a higher rpm before moving, forward motion starts from an rpm point, further up the power curve.
The best way to actually increase power period, is with lots of cylinder pressure, because it works thru-out the rpm range.
And of course, getting the air into the cylinders is always the hard part, so for bottom-end , the more cubes that you start with the better.
After this, your gears become a big deal., because the multiply your engine torque.
One of the worst things you can do, is install a big cam, with a later closing intake valve, because this will give up cylinder pressure, which, in an already low-compression engine, spells the death of bottom-end power.
