Olds 455, how much should i pay??

[RockHQ]

I went to look at an olds 455 today, block casting number 396021F. Looked like a good, 35 year old running engine with nothing polished up for sale, just unbolted from a car and left to sit, so not exatly a clean sight in that way. Complete from oil pan to carb, waterpump to distributor (a HEI distributor, which must have been added afterwards). It also has a new gear reduction starter, headers with 3" collectors (though the other one had been butchered a bit in an attempt to make it fit in a car) and original stock exhaust manifolds.

So, what would be a fair price for this 68-70 BB olds, which according to the owner ran a 1/4 @15.1 in a 4000lb car last summer?

Thanks!

-Axle

P.S It also passed our yearly emission tests, though the car was a 1980 which means they're not very strict.

[edit]
According to www.442.com a red 455 would be a 68-69 block, non-toronado.