i am building a new 350 for my 87 camaro and i have a mid 70's 350 will it work?

i wasnt sure if all te mounts were the same or if i would need to get a newer motor

Differences (assuming it's a complete mid-70's engine):

Intake manifold mount bolts - the center two on each side on the '87 are at 72 degrees, whereas the older engine has all of the mount bolts at 90 degrees.

Rear main seal - the '87 is one-piece, and the older engine is 2-piece. The flexplate/flywheel is different between the two types.

Dip stick location - on the older engine, it's on the driver side, and gets in the way of the exhaust manifold. If you use headers, no problem.

Valve covers - the '87 heads use center bolts, the older engine uses perimeter bolts.

Oil galley ports - the '87 may use a port above the oil filter that the older engine doesn't have.

Externally, other than the above, the engines are identical.