I've been looking up 105mm turrets...
Look what I've done!
All you need is;
M113 ACAV
105mm Gun set (short barrel & baseplate)
Turret from Vickers Light tank
Reverse flow cooling intakes from Saracen APC
Afterburner connecting ring from 1/72 Hasegawa F-14
...
Simples!!
And here's the finished vehicle, the Wolverine Assault Gun, seen here during Operation Commonwealth Storm, the joint UK / Canadian / New Zealand operation to remove Argentine forces from Queen Elizabeth Land after their illegal occupation...but that's another story...