Quoted Text
Comparing this photo to the MAZ-537G, the engine compartment looks very similar. Maybe not all 537L had YAMZ-240? If you are not going for 100% accuracy you could buy a resin T-34 1/35 engine (D-12 is based on the T-34's V-2 engine), put it into the MAZ and scratch build the other structures around it in the engine compartment.
Or, if you can find a TRP chinese type 89 series Howitzer/MRl series this kit has an engine very similar to this.