Sanden 508 on a Factory GM System?

[Ford Assassin]

Hey guys, I bought a Sanden 508 and Kwik Performance bracket for my '86 K5 that had a R4 radial style compressor from the factory. The rest of the system is stock except a new acumulator and varible oriface tube. I plan on using a R12/R134 replacement called Envro-Safe which is suppose to be colder than either R12 or R134 (according to reviews).

Anyway, I went to a local A/C shop with the truck and had custom hoses made. As I was paying for the hoses the guy decides to say, "You know that Sanden 508 isn't big enough for the factory GM evap, right?". I wasn't too happy he is telling me this after I just spent $100+ on custom hoses.

It doesn't sound right to me, but I am curious to hear what you Sanden conversion guys have to say. Since my K5 is in the middle of a 2wd conversion I have not run the system yet.

Thanks!!