Mark, leafspring cars had one box each side, under the seat area, not particularly big. I'd have thought the coil spring cars had similar, but couldn't swear to it. One clue would perhaps be the manifolds - according to Rinsey Mills, the Sports had the same cast iron manifolds as the earlier cars but with a longer intermediate pipe to compensate for the further forward engine position. He says 'silencers and tailpipes were the same as on 427 street cars', so I'd guess similar again, one box each side.