Yes, you should have someway to check the idle speed. The tach in the cluster will work, but the shop tach is better.

]quote]I just put my heads back on and want to check the timing.[/quote]

You did replace the knock sensor and wire, right?


More than tread lightly. Leave it like you were never there, nor anyone else.
'90 X-cab 4.88's 33 BFG AT's, rr ARB, Headers, Ignition upgrade, cold air induction.
'91 X-cab 5.29's 315's BFG MT's, rr ARB, custom bumper and flatbed