most good truck salvage yards have motors, &/or hotlines to other yards who can tell you who has what. sometimes they take the compression, oil and vacuum tests B4 they pull the motor, if it was say a rear end /side wreck. they usually have to drain all fluids after that cause of insurance reasons. that's a start. if possible try and get the mileage of the engine. go look at the actual vehicle the motor came from.
also look at this sites for sale and inliners site classified's,
http://www.inliners.org/ Ps, don't pass up a 230, 250 or 261 motor either.
