A small (200rpm) drop shifting into drive is normal.
It sounds like you have a vacuum leak somewhere assuming you have power brakes. If it is a manifold vacuum leak, you can find it easy enough by spraying some soapy water around the edge. It will bubble where the leak is. If you have a vacuum gauge, connect it to your vacuum tree and get a reading. It should be steady and around 20hg if I remeber right. If it drifts, then you jave a leak somewhere.
If the car ran fine before you replaced the hose, then the carb should be ok. You probably knocked a vacuum line loose somewhere.
This is just a guess but hopefully it is a starting point. Also, if you don't have any repair manuals, it might a good idea to pick up either a Chilton's or Haynes Mustang repair book. The Chilton's has a better troubleshooting guide but the Haynes has wiring and vacuum diagrams. You can find them at your local auto parts store or through one of the Mustang parts catalogs.
Good Luck.
Steve
http://chezdajez.mypicgallery.com/stevesmach1/my-72-mach-1.jpg
My 72 Mach 1 Q Code
It sounds like you have a vacuum leak somewhere assuming you have power brakes. If it is a manifold vacuum leak, you can find it easy enough by spraying some soapy water around the edge. It will bubble where the leak is. If you have a vacuum gauge, connect it to your vacuum tree and get a reading. It should be steady and around 20hg if I remeber right. If it drifts, then you jave a leak somewhere.
If the car ran fine before you replaced the hose, then the carb should be ok. You probably knocked a vacuum line loose somewhere.
This is just a guess but hopefully it is a starting point. Also, if you don't have any repair manuals, it might a good idea to pick up either a Chilton's or Haynes Mustang repair book. The Chilton's has a better troubleshooting guide but the Haynes has wiring and vacuum diagrams. You can find them at your local auto parts store or through one of the Mustang parts catalogs.
Good Luck.
Steve
http://chezdajez.mypicgallery.com/stevesmach1/my-72-mach-1.jpg
My 72 Mach 1 Q Code