“The SU-76 – Samokhodnaya Ustanovka 76 (“self-propelled carriage”) – was a Soviet self-propelled gun used during and after World War II. The SU-76 was based on a lengthened and widened version of the T-70 light tank chassis. Its simple construction made it the second most produced Soviet armoured vehicle of World War II, after the T-34 tank…. The SU-76M combined three main battlefield roles: light assault gun, mobile anti-tank weapon and mobile gun for indirect fire.” 
I remember looking at the one in the Tank Museum, Bovington. The driver hatch is open and clearly reveals the two engines (one for each track) arranged in parallel on the right hand side. There appeared to be no separation between them and the driver, which must have made things pretty unpleasant!
  
Tamiya 1/35 kit .