[Hallicrafters] HT-33A PL-172A Tube substitute modification

[jack m]

Hello group,
 
For 5 years, I have patiently searched for a useable PL-172A tube for my HT-33A amp.  3 EBay used PL-172A "wins" have been - well, you guessed right.
 
The PL-172 market is getting worse!  In favor of a winter boat-anchor project this year, I've decided to give up looking.   
 
As much as I would like to keep this near-mint amp original, the desire to actually use it with my HT-32A has won out.  I was discussing this on the air this past week, and the ham on the other end recalled another ham who had converted his HT-33A rig to run one of the ceramic tubes, but he was not a boat anchor afficianado and did not have any details.  He did recall that ham as stating that the socket and chimney/air cooling system, as well as the various voltage supplies, were not all that difficult or complicated to modify and adapt to the HT-33A chassis or design power supplies.
 
Is there anyone out there who knows of this mod, and where could I find the details?  As a "purist", I would prefer to be able to de-modify it in case the PL-172 market improves sometime in the future.
 
Thanks
 
Jack W3RU