Altered w/b Mustang HELP!!!

[kwikdraw]

Hello all, please forgive me for posting similarly in two places, my mistake, sorry. I need some quick advice and this looks like the place to get it. I will try to keep a long story short here. Due to the recent death of a friend, I have been offered the opportunity to purchase an altered wheelbase fiberglass mustang. The car was originally a holman moody drag car. My friend has owned the car since the late 60's - he saved tons of documentation on the car pics, magazine articles, etc. Anyway, I have a very brief amount of time in which to decide whether to purchase or not. The car is in very good (but not original) condition - currently 514 cid and a 'glide powertrain - (One of his friends made a couple passes in it last summer - @5.01 eighth mile) Does anyone have any idea what this car might be worth or how I might guesstimate it? I have owned a lot of old hi-po Fords, but am lost on this.. Thanks for any guidance you might offer!