I bought all my mounts from Crites ,came as a kit. I used all the brackets from a full sized 1970 model 429 Mercury wagon.I bought the whole car for 200.00 and used the motor and trans and every thing else for my swap.All the brackets were exactly as those used on the 71 429 Mustang.Very easy swap,I was able to even use the radiator shroud with a little trimming,When I got through I had a 71 Mustang engine bay,just as it would have looked from the factory.I even used the 429 2v air cleaner base,added a small lip to it,installed a factory ram air seal a ram air center (top).I was in a show next to a 71 429 car and you could not tell them apart ! I was very proud of the way it turned out,even took 1st place.
My point is it is a very easy swap and very doable if you know what parts to look for.Check out the 429 site and study it.Some things are the same.I will be happy to answer any questions.