Is this your type, approx 3" diameter, round one end, oval the other?
https://www.firebirdcentral.com/1977...p/duc-2023.htm
https://www.firebirdcentral.com/1979...p/10007530.htm
Not much is available other than the 4" version as used by the turbo 301 and big engines. Others have used items such as these industrial hose offcuts, even some of the resto shops had them on ebay when the standard 4" hose wasn't available, does a good job while nothing else exists.
Random googled link:
https://www.pegasusautoracing.com/pr...p?Product=3620