question about fuel pump housing
 

i put new cams in and when i got everything together my tuner came and said something is wrong with my fuel pressure. at idle it was only reading 70 and it should read 300.... so we took pump out and the piston/ lifter thing with the roller that rides on the cam wont slide in and out. had to loosen up housing for it to move... question is... is there some kind of gasket or shim for this? nothing was there when i took it apart... but now it wont move smoothly with the housing bolted tight...