Dave WM

One more thing, Maybe I should look at the valve guide seals for the oil in the cylinders. Most of the test running it idle, and this engine has a very high vacuum. I check it today at was 20in/Hg while idling. I suspect that could pull in a pretty good amount of oil on the intake valve seal.

more test, everything works fine with the engine, no oil noticed in coolant, no milk shake under oil cap, dipstick looks fine, engine runs well on test stand. compression looks good (165ish on all). however, I do seem to have a lot of oil build up on the plugs after short runs. Perhaps the oil control rings are not doing a good job. And I def failed the combustion gas in rad test (it will turn yellow after about 6-8 pumps. I tried it several times, flushed the rad etc... same result. So do I just put the engine aside and keep it as a spare (it would be fine I think as such) or do I do a partial rebuild (rings/head gasket)...

I have the 3.54 on the close ratio, and yes there is a bit more finesse required starting off. Not a lot but noticeable. living in flat land makes it a non issue, if you were in hill country and found yourself stopped on a uphill grade it may make it more of a problem. Up side is you can stay in 1st a bit longer. The CR trans I pulled was setup for a 3.7 based on the speedo gear that was in it. if you are in a lot of stop and go traffic it may be an issue. IMHO you should drive it as is for a while, you may find it not needed at all.

Garm, make sure you know the diff in the various ones, the 280z has final OD of like .83 iirc vs a .75 on a 280zx, it will matter as far as the diff you want. the key is a wide ratio vs a close ratio transmission.

which 5 speed?

You need to figure out the rear end ratio 1st before deciding anything else. It can be figured by counting turns on the input to the output.

if you want to go along for the ride on my adventures in swap on a 280

240 guy have to chime in on fitment, something may need to be trimmed to fit on the tunnel. Also getting the right shifter matters, On mine I used a ZX style and had to had an extender part to make it not sit so low. Also there maybe some issues on the drive shaft as far as the mounting flanges on the rear. I like my 81 IIRC ZX with a 3.54 has a .75 od so I can go 80 at 3k. But I don't even get in to it until 70. It maybe a bit more complicated than its worth on a 240 imho (trimming/diff swap/driveshaft swap). on the 280 it was bolt on affair, do it in a day. Also you "may" have to remove the exhaust down pipe for clearance, I did on my 280. that is a bit of a PITA if the bolts are rust welded to the manifold, I ended up breaking 2 of the 3 so off came the exhaust manifolds, replacing gaskets, fixing broken manifold bolts... just understand things can go wrong making more work. Is it all worth it, that's up to just how badly you want that OD.

I presume you want a 5 speed for better hiway speeds? if so the late years 280zx close ratio has a very tall OD .75, depending on the rear end that can make for a 5th that is use less until near 70mph. If you just want more gears and be able to use 5th you would want to make sure the final gear ration in the diff is more like a 3.7 or 3.9. So 1st thing you should find out is what kind of diff to you have? is it a 180 or 200 and what is the ratio. then you can better decide what your needs are as far as transmissions considering the end goal. The engine makes a lot of torque so lots of gears are not really needed to stay in the power band.

CO, do you have a spare camshaft that you can install? just want to know if there is ANY binding that you can detect.

you will get no help here in support for NOT getting it. Make a deal she can get a new couch if you get the car. I use that one a lot. Some how the couch deal never happens though.

so now I have to get a spare camshaft for my spare head for my spare engine....Paranoia is a difficult thing to overcome. better still, Camshaft phobia..

I am sure CO is going to do a post mortem with detailed looks at the fracture, its his nature.

I still think its the AFM that needs adjusting.

might as well... :) in all seriousness the might as well does happen, so you really have to assess your willingness to leave with a small leak. Just remember its a old car and the might as wells can really add up, including the follow up can or worms (broken studs etc....). So are you a leave it be, enjoy driving more that fixing, or a drop of oil is going to make you nutz. OK to be either but you need to decide. Also you will find that doing the work yourself is not just to save money but to make sure its done right unless you have a mechanic that really knows what they are doing and how to work on old cars. I find the biggest issue is not breaking bolts. Technique helps but eventually you are going to break one in a hard to get at location that can up the work factor a lot. You are going to have to do the clutch eventually anyway, it will chatter and slip etc... That is a good time to force you to fix other leaks. Just don't be surprised if you end up making some work for yourself along the way to fixing something easy (like breaking a bolt on the t stat housing when replacing a t stat...). I like my induction bolt heater, pricey but comes in handy.