found a 85 z28 with a 305(not exactly sure wich one) new starter rebuilt carb rebuilt tranny and flowmaster exaust plus all the receipts, needs a new idler arm and alignment the only real problem i have with the car is that it has 180k on the original motor wich runs great and has no lack of power the guy will take $1200 for it what do you guys think?

 

IMO buy the body, in other words, if the body is in great shape and it has some mechanical problems, they can be fixed. There's nothing you can do about a rust bucket. Check the numbers, you may have an L69 which is the high output engine (I think they still came in 85) 180k is a lot of miles, does he have any reciepts for things like timing chains or valve jobs? Is it a stick or an auto? does it have a disc brake rearend? Lastly, bring someone with you that likes.. say mustangs. That way they aren't emotionally attached to the car and will give you an independent opinion.
I'd say it all depends on the body, down here in fla $1200 might be a little high, but if it's an original numbers matching cherry and everything works, I'd say lowball him at a grand and see if he bites.

 

1200 was the low ball he wanted 1800 the body is in great shape no rust, the rear bumber could be replaced but its a no hurry thing. its a five speed and in great shape, tranny was rebuilt at some point. i dont know about engine work i didnt look at the receipts my friend did while i was driving it(my friend was there for the objective opion) i also have people looking for engines for me (i jumped on the engine swap idea as soon as i saw the add for the car) i was thinking i drive it nicely for about 6 monthes and then buy a new motor. and i couldnt look at the rear brakes the rims didnt allow much to show through and i was paying more attention to the tires and wondering where i could get stock rims.

 

first off the 305 ho is not as crappy as you might think, it will last forever.
http://83camaroZ28.tripod.com
That's my black 83 in the vid and the rpms are on the moon in the autocross vid.
If something has been modded, just make sure it's not butcherred. Sounds like it might be a good deal but really check over the body.
good luck with it.