I’m doing this with the motor installed.
Installed or not installed--doesn't matter.
So plug in the oil pressure sensor, leave the crank sensor off,
There's no reason to disable the crank sensor.
prime from the distributor,
I use a modified distributor, with the gear teeth ground off and a "handle" screwed-into the top. A priming tool is a viable method as well. Point is, DON'T TRY TO SPIN THE PRIMING TOOL TOO FAST.
When the engine is cranking on the starter motor, the distributor is turning something like 80-ish RPM. That's as fast as you need to turn the priming tool. Trying to turn it faster than that is hard on the drill motor; and much moreso if the drill is geared to spin the chuck at ~2000 rpm like most 1/4 or 3/8 drills. 500 rpm is bad enough with a 1/2" drill. At least the 1/2" drill is tough enough to handle that load for ~30 seconds or so. Assure you're turning the priming tool in the direction of normal distributor rotation.
Don't make a career out of "priming". The O-N-L-Y thing you're trying to accomplish is to displace air from the oil pump, oil filter, and the main oil galleries; and the oil galleries are going to be bleeding oil from the bearings and lifter bores starting the moment you quit priming. You are ABSOLUTELY NOT trying to lubricate anything by pressurizing the oiling system.
Everything that need lubrication was assembled with prelube of some sort.
put everything back together on top,
The only thing that wouldn't be "together" is the distributor and plug wires.
and see if she turns over.
If you installed the engine properly, why would it not turn over? Of course it's gonna turn over. Assuming the fuel system primes as normal, and the distributor is installed properly, (deliberately timed somewhat advanced for initial break-in--perhaps initial timing of 05 to 15 degrees advanced) that engine should fire almost instantly--which is what you want. Have a garden hose standing nearby to extinguish flames that SHOULD NOT HAPPEN, and to mist the radiator if it gets overly-warm.
After turnover, do you have any recommendation on good break in procedure? I’ve heard alot of different responses.
FIRST, with a flat-tappet cam, you need to run the engine with the throttle adjusted open, or blocked-open at ~2000 rpm for 20 minutes. Given a choice, I'll run it at 2K for ten minutes, watching oil pressure, coolant temp, poke my head under the engine to look for signs of oil, coolant, PS, transmission, or fuel leaks. Top off coolant as the thermostat opens and burps air into the radiator. Listen for "funny noises" including exhaust leaks. Shut the engine off with little or no idle-time. Let it cool. FIX ANY FAULTS you've discovered. Re-check all fluid levels. Re-start engine and again have the throttle set for ~2K RPM for the second 10 minutes.
In a perfect world, you'd have painted stripes on the pushrods, and used "special tool" valve covers with viewing slots cut into them, to make sure that the flat-tapped lifters--and therefore the pushrods--are spinning. These are my valve covers for Pontiac, but Chevy would be similar.
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IF (big IF) you used heavy, moly-based paste on the lifter bottoms and cam lobes as prelube, change the oil filter. 20 minutes of run-time with moly-based paste can plug an oil filter. Note that I'm NOT changing the oil, just the filter, and topping-off the oil. Some folks want to dump the oil, too. I think that's wasteful especially if you're paying big-bucks for special "break-in" oil. Re-start the engine, verify proper initial timing,
If this is a roller-cam engine, fire the engine and give it 10 minutes of ~2K rpm. Top off coolant as needed. Look for fluid leaks, listen for "funny noises". Shut off engine, verify all fluid levels, verify proper ignition timing. The lifters won't be spinning.
Then it's ready to drive. Grab your cell-phone, and take a little-used highway out of town. Drive 20--30 miles, turn around. On your way back into town, WHACK THE THROTTLE OPEN as far as you can
without the transmission kicking down from high gear. Depending on vehicle gearing and tire size, you'll be accelerating from 30 or 40 mph to 60+ mph. Then remove your foot from the gas pedal, coast back to 30-ish mph. Repeat whacking the throttle open without kicking the trans down to a lower gear, and then coast back to 30 mph.
Repeat until it stops being fun--6, 8, 12 times. You're specifically looking for heavy-throttle, high cylinder pressure to push the rings tightly against the cylinder walls, but not high RPM. There's really no need to run the engine faster than 3500--4000 RPM. The coasting part creates high vacuum in the cylinders, brings oil up the cylinder walls to wash away any wear particles. High pressure...high vacuum. High pressure...high vacuum.
NOW go home and change oil and filter. Verify all fluid levels. Assure no leaks.
Engine is broken-in and ready for service.
When it's me, I install a supplemental, bypass oil filter on "new" or newly-rebuilt engines. These filters will remove extremely fine wear particles, and other than the 20-minute regular oil filter plugged due to moly-based paste prelube, eliminate oil and filter changes on a new engine. The oil is kept clean-as-new for the service life of the bypass filter element, which can be tens of thousands of miles. The bypass filter is a permanent part of my '88 K1500; someday I'll put one on my '97; but you "could" remove the thing once you feel the engine has fully "broken in" at 200 miles, 500 miles, 1000 miles or whatever you feel comfortable with. My choice is old Frantz a_sswipe bypass filters, which use a roll of toilet paper as a filter element, bought used or NOS from eBay. Amsoil sells brand-new bypass filters using specialized filter elements, there's a company or two that have updated the Frantz filter, and there are other companies that sell bypass filters also.
