4 speed ka-booom !

So, now I read all the posts. When you twist splines like you did it's 100% clutch. You will KILL 40 spline axles too (don't ask), bend 5/8ths drive studs and all the other crap.

You need STEEL shift forks. Don't grind or "taper" the drive hubs. That won't do anything. All you parts look runable in the pics. Don't get excited about cluster gear clearance. As long as it's in spec, let it go. I had a friend spend big $$$$$$$$$$$$$$$ trying to "tighten" up Chryslers "loose" tolerances and it didn't do anything except waste time and burn more cash than required.

Again, THINK about slick shifting, about why it does and why it's done. Then think about how you can slick shift and make it streetable. You can do it. You can slick shift it yourself, in your shop, with a hand grinder and some aluminum oxide grinding stones. Never use carbide on the gears. Grind EVERY OTHER TOOTH off of the 36 clutching teeth on the gear (so you are removing 18 teeth) and then remover every other tooth on the slider. Do it to 2nd, 3rd and the input. DO NOT REMOVE ANY TEETH FROM 1ST GEAR AND ONLY REMOVE HALF OF THE TEETH ON THE 2ND GEAR SIDE OF THE 1-2 SLIDER. Then think about what you did, and make it streetable. You can do it. You still need a better clutch (actually the correct clutch). I'm telling you, you can do it, when it's done correctly, you wife can drive it. If you really want to be badazz, you remove 2 teeth and leave one. We used to call that "Pro Shifting" cuz we all know if you want anything to be badazz, you just add PRO to it. But that is a waste of time. You don't need it. But you need the soflok and the slick shift. BTW...don't base your shift RPM on where max torque is, or whatever you were saying earlier about it wanting to rev past 7K but max torque was lower. That is why stick guys using off the shelf cams or giving up big ET. A conver slides into the next gear. The stick pulls the engine down further. So how well your engine recovers RPM is almost as important as how much HP you make.

I threw that last bit in just for free.

Keep the stick.
Spend your money correctly the first time.
If you don't learn clutches you can't build anything strong enough for the abuse.