cant set installed height

[LowBuckX]

Was told to set my installed height at 1.800 But The closest I can get is 1.745.
This is with trickflow heads and spring cups already installed. Obviously adding shims would make it worse.

Why would I need to have a set of heads machined to get the correct height when supposedly they are set up for cups already??

*****IN ADDITION***
These valves seem to have very large margines. Would a good valve job give me the added height I need? I wouldnt doubt if the previous owner/builder installed the valves with out doing any sort of grind. A basic 45* is on them now.

Just to clarify this is on a hyd roller cam and howards springs 98213

120#@ 1.800 375#@ 1.250
@ 1.75 they are 145#

[Zee]

Crane makes valve locks that will give you an extra .050 of installed height. Make sure you get the machined ones as they offer two types. Here is a link: http://www.cranecams.com/?show=browseParts&lvl=3&prt=2128&action=partSpec&partNumber=99095-1