Good point about paying attention to the redlines of the accessories when you change the pulley ratios.
Your rad fans shouldn't run much with the exception of stop and go traffic. You can probably get away with the stock CS144.
8ga or 10ga charge wire from the ALT BAT terminal to the starter BAT terminal will work just fine.
If you're really pulling that much power you can get the four terminal AD244 from 2005 and earlier that doesn't require control from the PCM.
__________________
1959 M35A2 LDT465-1D SOLD
1967 Dodge W200 B383, NP420/NP201 SOLD
1969 Dodge Polara 500 B383, A833 SOLD
1972 Ford F250 FE390, NP435/NP205 SOLD
1976 Chevy K20, 6.5L, NV4500/NP208 SOLD
1986 M1008 CUCV SOLD
2000 GMC C2500, TD6.5L, NV4500
2005 Chevy Silverado LS 2500HD 6.0L 4L80E/NP263
2009 Impala SS LS4 V8
RTFM... GM Parts Books, GM Schematics, GM service manuals, and GM training materials...
Please include at least the year and model in your threads. It'll be easier to answer your questions.
And please let us know if and how your repairs were successful.