Yes.. it is available.. We have not done an official release of the new tail wheel spring and it has been tested on the 5-7 aircraft. While I suspect it will work fine on the IV the angle of the spring may be an issue with some tail wheels. Works great with the 8" pneumatic Maule, ABI-3200, Scott 3200, and Matco's 8" and 10". (most of the testing was with the ABI-3200 and the Matco)
$349.00 for the spring and mounting hardware.
$59.95 for the draw spring, clips and chain.