Musing on Litvak's 'AltCan' scenario again ... in this case, post-WW2 Royal Canadian Artillery and Royal Canadian Horse Artillery. In my version, most heavier artillery vehicles are based on updated Sextons with Canadian Dry Pin tracks. But, here we have two exceptions to the rule.
One is a Grizzly-based gun tractor - the Canadian Tracked Artillery Tractor, Heavy (CTAT-H). The CTAT-H has a Grizzly (ie: Canadian Sherman) lower hull mated to the upper structure of the US M4 high-speed tractor (CTAT-M in AltCan CA service).
The second is a self-propelled gun based on a US M12 hull. The standard heavy self-propelled gun was the CSPG-140 Archdeacon mounting the 140 mm CHFG-140 (Ordnance BL 5.5-inch Gun). This experimental version - the Cardinal 149 SP (149 mm CSPH-149) - mounts the much longer 149 mm CHFG-149 (captured, ex-German 15cm K 18) heavy gun. After trials, the overly heavy Cardinal was converted into a Canadian Artillery Support Vehicle, Heavy (CASV-H) akin to the US Army's Cargo Carrier M30.