Freeze plugs
Some starters are intended for a 153 tooth flywheel, some for a 168 tooth flywheel. Most 307's had 153's, and most 350's had 168's, but you could put a 153 on a 350 or a 168 one a 307. Both engines are internally balanced, so as long as you have the correct starter for the flywheel, it will work. The one other difference between Chevy starters, is the length of the armature. The longer one is heavy duty, the shorter one is standard duty. Either will work as long as it's mated with the right flywheel.
There could be different reasons the security light is coming on in your Chevy Trailblazer. The fuse could have blown or there could be a wiring short.
You have to replace the seal/gasket between the fuel pomp and tank
It could be the starter drive, the solenoid, or the ring gear itself. Best to pull the starter out of there and see what's going on.
It could be coming from your heater core, may need to repair or replace it.
yes. a starter made for the 168 tooth flywheel would not engage a 153 tooth flywheel.
Could be either a defective starter drive or a broken tooth on flywheel Try turn the engine manually (large socket on crankshaft) to see if it will start- if so problem is a broken tooth - if not problem is probably a bad starter drive. (make sure vehicle is in neutral if std.)
Could be the brakes are gone or it could be a hub and bearing assembly about to fall off the front of your car.
Defective starter, or a problem with the flywheel. You need to check the starter and then remove it and check the flywheel.
Bad starter, bad flywheel/ring gear, bad starter/flywheel alignment.
Bad torque converter?
Don't do that too often. If the starter Bendix is not fully engaging the starter gear into the flywheel, you could be wearing the flywheel. That could be expensive. Remove the starter and inspect the flywheel. Slowly turn the flywheel by hand and inspect the entire circumference of the gear.