what is your end goal with this?
30% on stock fuel has its place, but performance is not one of them.
tow rig, ya. same fuel, shorter pw, cooler egt's, more down low, much less up top, and the 71/59 i highly doubt are going to be large enough.
we spec'd my cam as a tow cam, drive the turbo's a little harder to light them faster, and while the turbo's spooled insanely fast, they were driven to hard for what they were, and shelled about in about 25k miles.
i now have rcd's 75/59, no wg, and their borderline same, though they pull crazy harder up top. i'm soon going for a wg, and if you go with 71/59, you better gate the hell outta them depending on how you spec your cam.
i will say, that i have ridden/drove a few stock fuel trucks, when i had my 71/59, that had same turbo's, tunes, pretty much same truck aside from color, and mine was very much noticeably more fun with the cam, valve train upgrade, and delipped pistons compared to their deleted stock motors. aside from my cam, there is nothing we did that could be really considered performance, aside from the cam i suppose. it's all reliability.
take the time to do springs, p-rods, pistons, and i did hardened valve seats. when we pulled mine down, every valve seat was cracked except two, and they were able to put hardened seats in to save the heads. was much cheaper. which gets you a valve job.