Pull what - It should be the work of a split second to glance inside and note these during the takeoff roll - any takeoff roll - do you not always check that the ASI is alive anyway?
Unless there's a confusion and you're thinking that you check them rolling down the runway prior to starting the takeoff roll?
I'm personally pondering how you detect a loss of power with a CS prop - other than shaking, banging, or dramatic loss of power, likely to be quite insidious..