Small Block Chevy won't turn over

1977 Chevy El Camino V8 350. Professionally rebuilt engine and transmission and then assembled by me (much less than professionally). Car has not run well since rebuild, but has run. Was driving last week, but engine stalled. Tested the battery: it was toast, so replaced it. Starter and alternator test fine. Now engine will not turn over. Starter clicks/engages but can’t turn engine over. Engine cannot be turned over manually with a breaker bar on the balancer bolt. Please tell me my engine isn’t seized!

I can’t do that because it’s a distinct possibility due to lack of oil, something breaking or coming apart, etc.

Automatic or manual transmission? (I’m assuming auto here)
Any noises or symptoms of any sort before this happened?

Sorry I can’t be specific as to what the problem is but it doesn’t sound very good at this point. You might pull the spark plugs out and examine them to see if they’re normal in appearance. (Tan on the tips, etc. with no white glazing, glassy appearance, etc. Point being to make sure there was not an excessive timing advance problem involved.)

Thanks ok4450. There was definitely oil throughout the engine, which is part of what is throwing me.

Automatic transmission.

The engine was definitely not properly timed. I was test driving it to see how bad the timing was when it first stalled on me. I was going to try to get it as close as possible by ear before driving it the full distance to a friend’s house (he owns a timing light). If there is an excessive timing advance problem, is it solve-able?

Chances are it is seized. If it was running bad because the timing was that far off. It could be the distributor was installed incorrectly and affected the oil pump.

Loosen the starter bolts and then see if the crank will turn. If not shimmed correctly the starter bendix will jam into the flywheel and stop the engine from turning.

Pull the engine, take it apart, and try again…

I would not think a timing issue would cause a major problem on a test drive. This would crop up more than likely on a highway drive at speed and generally have a few symptoms involved such as overheating, a pre-ignition rattle, etc.

There are a number of things that it could be. Some possibiities could be too tight an oil clearance on a crank bearing, piston ring fit too tight, broken oil pump driveshaft, etc are just a few of them.

Since it stalled while driving and is now seized odds are something gave up internally.
A start might be to pull the distributor and make sure the oil pump driveshaft is still in one piece.

So many people attribute so many driveability issuse to the timing, most that just aren’t a possibility. I was very happy when the days came when timing became non-adjustible, then you don’thave too spend hours on a car the boss wrote up as “set engine timing”. When you tell the boss that the engine does not have a ignition timing issue he says “find out what is the problem , I will pay you what it is worth” and never does because the customer has a fit when he gets a 2 hr diagnostic bill, "I just came to get the “motor’ (they always say motor) timed”.

Years ago it occurred to me that “timing” was an empty well. After a few people brought me cars and asked that they be timed and when picking the cars up demanded that they obviously weren’t timed correctly because they were still not running as perfectly as they should. And the customers insisted that they had replaced the plugs and points, cap, rotor and wires and had everything PERFECT except the timing. Therefore I didn’t know what I was doing unless I could prove that my timing wasn’t the cause of the problem continuing. Which left me giving a free diagnosis. I long ago set my price for timing an engine equal to a complete tune-up.