Hi, Ron
I upgraded my 351w motor mounts to polyurethane units made by Olthoff Racing, a SPF dealer in NC. They are of excellent quality - I highly recommend them.
You can contact them by phone at 704-647-9924 or visit their website at
http://www.olthoff-racing.com/
They make several performance bolt-on parts for the SPF - full width roll bars, bilstein racing shocks and springs, and more.
Great people to do business with.
Jim Kellogg 887