if it's a valkyrie, i just might have an original manual for one laying around.
most of the old ones like that used either a volkswagon, porsche or corvair engine - the original VW chassis would be hard pressed to mount a v8 into it. it can be done (aka the 350 chevy into 914 porsche, 911 porsche converstion from renegade hybrids) but it would take a lot of fabrication.