cherokee high rpm knock- only in acceleration

[ratrod51]

So fellas, i have a 94' cherokee 4.0 high output. it idles and runs good- 139k. BUT when you first start it it has a knock/rattle but goes away immediately. when you rev it pretty high it has a hard knock. it goes away if you rev it up and hold at that rpm.... or when your driving it knocks right before it shifts and when it shifts it goes away. i just replaced the timing chain... made no difference. thinking leaky lifter, bad wrist pin, or rod bearing.... any suggestions?? thanks guys

-Tye