Talk with Don at Airflow Perormance
I needed one and spoke to Don at Airflow Performance. He cautioned me to ensure my spacing stackup with my cowl would work with the spacer (some times a problem with the stock cowls) At times it's an easier fix to change out the studs on the manifold. In the end, i had him make me a spacer, which was fairly inexpensive and provided quickly. Don has given me plenty of expert advice already, so I felt good seeing him some money for a part I knew I could have built.
YMMV,
David