I just did a 383 Blue Print swap in my 89 K1500 SCSB and am running a holley sniper. Have a sniper on the 496 in my 68 Camaro as well. They've worked well for me. Most problems are install based. Do a good clean install, and you shouldn't have issues. Holley has been great for support as well...
Just did one in mine (blueprint 450hp/tq crate), plus gears to fit the tires. Hauls ass now. I think I may need a different torque converter for the 700R4, but I'll wait until I toast it.