Unit change out help?

[genuinejd]

I have an old 1976 Frasier Johnson 2 1/2 ton unit on a single story house. This is a gas pack on the roof, with side discharge. Model number is 80wr30e1na.
My question is does anyone make a unit that matches this side dicharge, if you are looking at the unit from the plenum, the return is on the left and supply is on the right. I am looking at using a 3-31/2ton unit. I have looked at a couple of different options on the data sheets from different maufactures and they all look to be opisite from what I have up there all ready.
I am looking to do this job as quickly as possible, there is a tenant in the house already, I have to drive 150 miles one way to the job and I have only a small window of time, when I can do the work.
If anyone knows of a unit, that I could use to do a quick swap on this house, then I would greatly appriciate it.
Thanks for all of your help and ideas ahead of time.

[76Tech]

not to hard to change it over. 2 guys about 8hrs.