starter pinion not engaging flywheel ring gear, fixed, SR11X SR17X Options

[shuie]

I've pulled my spark plugs and am trying to use the starter to build oil pressure before firing my engine.

Car has been built from the ground up. Pretty much everything is new. New engine, new flywheel, new/reman Bosch starter & solenoid, new battery cable, new ground cables, new engine wiring harness, etc.. Battery is an Optima that is not new, but is fully charged.

I turn the key and I can hear the starter pinion grinding on the flywheel ring gear. It sounds like a hammerdrill. I shorted the 12V to the switched 12V terminals on the starter with a screwdriver and I get the same grrrrr sound. I've shorted the 12V terminal on the starter to ground and verified that the starter spins freely without the grrrr. So, I think this means that the ignition switch, starter motor, and solenoid all check out.

I pulled the starter and can see the grinding on the flywheel ring gear from where pinion is trying to engage the flywheel. I have nothing else to do today, so Im going to bench test the starter and check the voltage drop across the battery.

I double checked the engine/trans mating surface and everything is flush and tight. I do have the brass bushing on the end of the starter pinion. Everything seems to be bolted up fine.

My battery cable is a 60" piece of #2 stranded welding cable. Battery and trans grounds are also #2 (FLAPS cables). Ground surfaces are clean and tight.

Does this sound like a wiring issue (cables too small) or some kind of alignment issue with the starter and flywheel? Am I not getting enough juice to fully extend the pinion, or is something misaligned?

TIA