Well I'm not sure what kinda $$$ you have in the big block, but IMO that sounds like a very good deal to me,, around here a complete LS1 pullout with the stuff you listed would go for 3500-4K or so.
I've been around alot of the LS1 fbodys and I'd guess that the combo you have listed will yield about 370rwhp and the torque should be in the same range (I'd bet 20$ that I'm within +/- 20 hp),,, and it'll be alot better on the gas budget than the big block!
If you get it can I suck up enough for a detailed picture of the harness,LOL!
*edited to add: if you need any measurements made to verify how it'll fit just pm me. The alt and a/c compressor both mount low on the motor and could cause problems with frame clearance. The fbody oil pan is a rear sump,,,,