How high do you have your deck set? How tall is the grass when you cut it? If you want to mulch these two measurements are as important as the speed of the tractor and the engine. If you mow at 2" you need to mow before the lawn is 3" tall (the rule of thumb is to cut off no more than 1/3 of the blade height when mulching).

aware of rule of the thumb, didn't mention cutting at 3" height, grass not too tall

I don't think Gators will help you. I have both and under spring conditions, i prefer to use Gators with side discharge. When summer dry conditions resume, the mulching is better but even the "1/3 the leaf blade" cutting rule is too much. I've even got the "high performance mulch plug" which is an improvement over the mulch cover but still can be overwhelmed.

I use the gator blades and side discharge. With the mulching cover on it always left clumps of clippings.

zeusrck1

did that solve the clumping problem

So is this a new problem, or has it been doing this since you purchased it?