71 Dart get 408/ Trick Flow Heads....

the heads i bought have the spring height at 1.90 with 120 lbs on the seat....cam needs 140ish on the seat...I was told by someone with a lot of knowledge that the springs on these heads were PAC 1903 which are the same springs I use on the eddy/Sm heads...I checked the specs on the springs and yes he was correct same spring at different installation height....so I shimmed them down to 1.800 installed height that the Eddy head uses.....

there was a shim on the head already...dont know what it was ....checked the height with that shim on there...I got 1.89 inches....I added a .060 and a .030 for a total of .090......rechecked height and it was at 1.80 inches.....