Excessive oil pressure and top end noise 2.7

Have 96 Tacoma 2.7 just replaced lifters and timing gear and chain kit still have noise that does not go away when warm . Sounds like top of engine . Also installed mech. Oil pressure guage has 100psi when cold but will fall to around 45 to 50 warm 15-25 at idle any ideas engine has 174,000k. Thks. 5 speed transmission
If you hold brk you can make noise go away at certain rpm under load