1999 Chevy Tahoe will not cool properly

[hekg]

Hi all, I've been going crazy with my dual a/c truck and a system that refuses to cool properly. I'm currently getting about 68 degrees out of the front vents on max cool and about 62 out of the rear vents.
The main issue driving me crazy is that I have changed literally everything in the system except the rear evaporator and rear lines. Just to outline what I've done, I put in a new parallel flow condenser, new sanden 4440 compressor, new front evaporator, new front lines, new orifice tube in y pipe and new rear txv valve. Plus I also removed the heater core so that there is no heat at all going into hvac box.

I added 11 ounces of oil, vacuumed the system down and let it sit for two hours and it held just fine then I charged it with 64 ounces of r-134a.

Now, since almost everything is brand new, what would prevent it from cooling properly and why does the rear ac cool much more than the front air? Please help me because I'm at my wits end with this truck.
Thank you!

One more thing, the other day as I sat in the truck with both front and rear air on max cool I decided to turn off the rear air to see if it would help the front but it actually made the front air get even hotter. :/

[Cusser]

Attach a real service gauge set and post both high side and low side pressures at 2000rpm after a couple minutes of operation.

Are you positive that the front system has just ONE orifice tube?

[JohnHere]

In addition to what Cusser said, bear in mind that a properly charged system with front and rear A/C will show pressures that are somewhat higher than vehicles with front-only A/C.

What color was the OT that you installed? It should be yellow (or beige) and white—0.062" orifice—with a single black or green o-ring.

Did you by chance add 11 fluid ounces of oil to the several ounces of oil already in the replacement Sanden compressor? If you did, that would also be a reason for the system's poor cooling performance.