88 celica all trac

i found a toyota celica all trac an 1988. when i first saw it, it looked like it was brand new i went inside and it was mint with 126k on it. i turned it on it ran smooth i cheacked out all of the electronics the ac and it all worked grate. but when i accelerated it started clicking loud, i think it was a valve but im really not sure. the thing i want to know is how much would it cost to get a new head or just replaceing the bad valves or is it more complicated then that. the car was selling for $3000 but he said i could talk him down since it has a bad head or somthing??? how much should i offer him and how much would it cost me to fix the problem (problems)

Go to celica.net, celispeed.com, and alltrac.net there are alot of alltracs and celi's that year on those forums.

Talitha