i bought the proper 70-72 big block frame mounts for my 81 z28 from classic ind.but they don't match up with the holes in the crossmember,does anybody know if there is a template or something to put mounts in the proper spot,i can't get a straight answer anywhere,any help would be appreciated.

 

You might have to set the motor and transmission in the car. If it was me I would have the drive line and everything else, like the transmission cross member bolted in. Then you would know for sure where to put the motor mount holes.

 

Any reason you didn't just bolt the BBC into your car with the SBC mounts? They would have bolted right up with no issue if you used the SBC motor mounts also.
I don't know of a template. I'd drop the engine in place and either tack weld the mounts so I could rill them with the engine out, or if possible mark the holes to drill with the engine out. PITA, but not much else to do.