The 2245 is a 14mm plug with a 3/8" reach and a heat range rating of 5. The AER72 is not good substitute, it is the equivalent of an Autolite 2407 which is a higher heat range plug plug with a 1/2" reach. The higher heat range might be good to prevent fowling but it can also lead to run-on when you shut the engine down.
Suitable substitutes are:
Champion 517, ORD02, XMJ17
The other problem I see is the longer length outside might not allow the cable to make good contact resulting in lost power or misfiring.
These plug are avallable from multiple sources for around $12 or less, why take unnecessary chances? There listed here for $5.50 ea: http://www.autopartstomorrow.com/part_n ... spark-plug