1994 Silverado Low side pressure pegged out with a/c off?

[1slos10]

I recently LS Swapped my truck and had issues with the compressor kicking off due to pressure going way up on the high side and you guys helped me get that part starightened out(Big Thanks!!), but now I've noticed when I switch the air on and noticed that it almost stalls the motor, when I cut the air on, so I hooked the gauges up. When running and a/c switched on the low side is around 55 and high side is around 275. When I check it with the a/c switch off, and the truck idling the low side gauge is pegged out, and high side is resting near 125. When I cut the truck off the low side stays maxed out, and does not equalize. Any ideas?

Running a new R4 Delco Compressor, accumulator and condensor.

Thanks!

[Dougflas]

When not running, the system is equalized meaning both hi and lo side PSI are the same. The lo side gauge does not indicate the same PSI as the hi side so the lo side pegs. Perfectly normal.