Here we go again, WHAT SPARK PLUGS

It sounds to me as though the idle mixture is too rich and the squirters are too small. First I would adjust the idle mixture when warm and in gear to the highest possible vacuum reading. If you have have to screw the idle mixture screws almost all the way in, you may have a blown power valve.

Next, if it is bogging at no load, I would bump up the squirter size and see how it runs off idle from a dead stop. Then comes top end WOT throttle testing in a safe place.... This will be how you determine your main jet size.