87 f150 302 engine oil leak. Fixable?

I have an oil leak where engine and tranny meet. I have been quoted $600+ bucks by Ford house and a mechanic to replace gasket with no guarantee it will stop leak. The leak drips on the exhaust pipe that crosses over and puts out some smoke/smell. Inspection is coming up. Will this hurt me in TX DFW area? I think we have the same emission set up as in Houston. While driving it is not so bad except at long red lights, but during the inspection it will smoke because there is no wind passing under the truck. What about an oil stop leak additive? I check the oil regular and add a quart every month for a truck I drive only on the weekends. I think it keeps dripping after I park until the pressure equalizes. P.S. The tranny is due for a fluid change soon. Auto.

I am not sure why any good garage could not stop it from leaking? Did they tell you what is wrong?

Probally needs an oil pan too.Ford oil pans are known for rusting out and are in stock at most dealerships