Strictly from the thermal output to parasitic drag perspective the scroll compressors have about a 10 % advantage over the recips as a class (80% Vs 70%). What Warpspeed said about the performance "clipping" can be the negative about scrolls. Their efficiency just hangs in there to about 7000...
The TRS090 Sanden compressor comes in two flavors. The Honda version is designed to rotate CCW (viewed from the drive end)(engines that face drivers side). This would not be a good choice for you SBC (rotates CW). The Chrysler version is designed to rotate CW (engines that face passenger side)...