As for oil pressure - pushrod motors don't have cam caps... those are in overhead cam motors.
Crank main caps and rod caps will absolutely be the determining factor for oil pressure.
Rule of thumb is oil pressure should increase about 10psi per 1000 rpm's... Toyota's have REALLY low idle psi tolerances (as in - low oil pressure on more modern engines is around 3-5psi at idle, even though most of those engines make 10-30psi at idle).
Water pump on an SBC is easy to get to whether the engine is in or out of the vehicle (swapped mine out in about an hour and a half, taking my time, and I have a couple extra coolers in the way). As for the oil pump - you can pull it and see if it's worn, but probably not. Might be a better idea to pull some bearings and take a look at them.
I have no real experience with oil pumps, just that they seem to work almost forever. If I was rebuilding a motor I'd replace the oil pump. But, otherwise as long as you have good oil pressure I think I would leave it alone.
toyotaspspeed, I'm not sure that you were referring to my post when you mentioned cam caps. But, just in case you were, I was talking about just the bearings only. Now, I do agree that, in my knowledge, only overhead cam motors have cam caps. But, in order to keep from confusing those who may not have a great deal of knowledge about motors, pushrod motors have what looks like a freeze plug in the block that seals the back end of the cam. There is a big difference in looks and serviceability between cam caps and "freeze plugs".
Rick, on the subject of water pumps, I would have to agree with toyotaspeed, they are usually very easy to access on an SBC for replacement. However, if the cost of a replacement pump is low enough that the frustration factor cost of having to replace a pump when in the vehicle exceeds the cost of the new pump then you may want to change it when the motor is out. That's going to be your call.
Just to clarify why I specified SBC water pumps, I recently helped my son replace a water pump in his Acura (overhead cam motor). That was my first experience changing a water pump on an overhead cam motor. Hopefully that is JUST a Honda Motors design, and not an example of all overhead cam motors. I have never had such a rough time changing a water pump. The water pump is run off the timing belt, and you have to take apart almost all the front of the motor just to access the water pump. It is an interference fit motor, and whenever you replace the timing belt you also replace the water pump, or vice versa, just because of the difficulty of access.
Don
Thanks, both of you, for the very detailed input.
I think I may just run them, for now. There are a lot of very big unknowns with this engine - I don't want to dump a TON of money into it. I keep going back and forth as to whether or not I want to swap it. I really can't get a good feeling for whether the rings in this engine are good or not.
To recap:
Positives:
No smoke at idle
idles beautifully, doesn't seem short on power when driving
Great compression (139 - 150 across all cylinders) - but this could be because the cylinder's full of oil...
Good oil pressure (so probably good bearings)
Negatives:
All spark plugs black. 2 or 3 showing oil, the rest might be carbon
Smoke out the valve cover breathers - BUT I have no PCV setup on this engine just passive breathers which could be part of the problem
SOME blue smoke out the tailpipe when the engine is revved when sitting (nothing noted while driving, however)
Only about 15 In. Hg. of vacuum - which, to my understanding is on the low side of acceptable.
Honestly, I think the biggest variable right now is truly the Quadrajet. It's WAY too much carb for the engine (800 CFM Buick). Rebuilt by me (intermediate mechanic at best). It also has a warped air horn, limited choke functionality and, currently, is running way rich and flooding.
I think what I'll do is replace the carburetor with a known, good entity (SMI Chevy Quadrajet, set up for a 283), then run all these tests again.
So many of the "negatives" above could be issues with the carb, not the engine:
Bad vacuum - leaky throttle plates/warped air horn
Fouled plugs - rich mixture
Really, the smoke out the breathers is my biggest concern. There's quite a bit from the driver's side. Granted, with no PCV, SOME is inevitable, but the only way you should be getting smoke from a breather is high crank-case pressure, and the only cause of that is blow by, and the only cause of blow by is worn rings.
So I guess I'll wait the 6-8 weeks for a carburetor, bolt it up, tune everything and run the tests again. I'm guessing a leak-down tester is in my future.
