When one turns the key to the "on" position does the starter bendix extends from the starter housing enough to come into contact with the flexplate? The reason I ask is so I can ensure there is enough space between the bendix and the flywheel teeth mesh properly.

 

No it only moves when put to the start position.

 

GM (Delco Remy) starters don't use a Bendix drive. The starter solonoid, mounted right on the starter moter,does two things: makes the electrical connections, and operates a lever that shoves the drive gear into the flywheel teeth.
Older Fords often used a Bendix drive- you would see the starter solonoid mounted on the side or rear of the engine compartment, separate from the starter motor. The Bendix drive used a spring and a spirally cut splined shaft to get the starter gear to engage the flywheel. When it failed, you would hear the starter motor spinning and whining without engaging the flywheel or turning the engine....
There is a clearance spec for the flywheel teeth/starter gear, but I can't imagine how you would get to it unless the transmission and bellhousing were removed. Maybe if you just pulled the dust shield/clutch cover.

 

I trick i use is to lift the motor lead from the solenoid to the motor and energize the solenoid with a battery charger. The motor lead is that solid lead the comes straight down from the solenoid and if lifted prevents the starter motor from turning. Lift your batt positive and or ground first. Then connect a 6 amp batt charger to the solenoid - positive to the purple wire (not the red wire(s) on the large post terminal) and negative wire to that lead u just disconnected to the starter motor. U may need to energize that purple wire from up top as that solenoid terminal is difficult to access. As soon as the batt charger is turned on the solenoid should energize and the pinion gear will extend out.
I recall the gear/flywheel clearance spec was something like 0.015" and i measured a paper clip to be close enough. Just used a small paper clip wire diameter for the clearance check. Yes u can remove the bellhousing inspection cover to access the flywheel/pinion gear.

Hope this helps and let us know if u need more help here,
cardo0

BTW thanks for the correction, now i know what to properly call the pinion gear.

 

Just add some notes. U will have to pull the starter to remove the bellhousing inspection plate. This would be the best time to disconnect the starter completely and install 2 temporary wires. One wire for the positive batt charger to the purple wire terminal on starter. The secound wire to the disconnected solid lead terminal that used to connect the starter motor to the batt charger negative. U can try this bench wiring before reinstalling the starter and should observe the pinion gear extend when the batt charger gets powered up.

Good luck #7,
cardo0

 

You could remove the solenoid and manually move the drive in to the flywheel to measure.

 

Roger's way is best. This will be safer and will not cause damage to the solenoid. If the solenoid is engaged to long damage may occur to the windings in it.

 

paperclip is the way to go. I did find this challenging to measure on my mini starter though. for whatever reason the bendix did not want to come out for me when I tried to pull it or pry it.