over pressurized radiator

[black91-GT]

Hey guys
I just installed a new short block in my car and now my cooling system seems like it is over pressurizing, my upper hose gets hard as a rock and the coolant won't vent into my overflow can. If I install my cap so its not tight it runs fine, I've replaced the cap and burped the system but that hasn't helped

 

[black91-GT]

ttt

 

[IndyBlk5.0]

so no fluid is being pushed or being sucked out of the resevior?

 

[black91-GT]

if the rad is low it will suck it out the overflow, but it won't allow it to vent to the overflow and it acts like it just backs up in the rad/upper hose. plus I noticed I'm getting some small boubles through the rad with the cap off