I rebuilt the vacuum system in my (now sons) 83 300SD. It had a brass restrictor in a couple of the lines to keep the vacuum actuators from acting too fast. Removing them may cause a large thump when some of the actuators operate. It may also increase stress on the mechanism. Not sure if your thottle valve is for the same prupose but it may be similar. Hope this helps.

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D. Blake
86 300SDL 340K (for sale)
83 300SD 205K (gone)
06 Chevy K3500 LBZ CCLB 50K
94 Chevy K2500 6.5L TD 250K (gone)