Are we talking about a gas chassis coach? They typically have longer rear overhangs than a Diesel pusher, so 37 vs 35 can make a difference. If its a diesel, though, the extra length will be between the wheels (wheelbase) rather than behind the axle, so less chance of dragging the tail.
In any case, you need to look at the length of the rear overhang on the 37 and the wheelbase length. If it's built on a longer wheelbase chassis than the 35, it may not drag. If the same wheelbase, it probably will drag.
Is the lifter you are asking about an add-on air suspension, e.g. the
Loadlifter 5000? If so, it may or may not help depending on the rear suspension of the 37 footer. The lifter may not be able to raise the rear end much from its normal level - it's purpose is primarily to prevent additional sagging as load is added. If the rear suspension on the 37 is already handling the load well, the air spring might gain you only an inch or two of extra height when fully inflated. It's often the length of the rear overhang that causes the problem, not suspension sag.
