I just recently purchased a 1978 280Z that is fairly good order. But as usual for older cars it needs to have some work done. It is running rich so I have downloaded the FSM and started performing some checks and I need Thermotime sw and Water Temp sensor. But after looking at the manuals I'm not sure if it is a 1978 engine. The manufactures plate reads that it build 2/78 so I know the car/chassis is a 1978. But I'm not certain if it is the a 1978 engine. Is there anyway I can tell if in fact it is a 78 or 77 or even a 76 engine?

What's the serial number of the engine? It should be on the top of the block just below the #5 spark plug.

A 78, 77, or 76 engine would be pretty much the same. Some of the components changed like the Air Flow meter, the fuel rail, etc. but as long as you have the correct componenets for a 78 connected to the engine it will work as it should. Differences on the 78s from the earlier years include an internally regulated alternator, no fuel pump contacts in the AFM along with different circuitry to actuate the fuel pump,

Thanks for the info. The number on the block is L28 353159

Of all of the 280's entered by people in my online spreadsheet that's the biggest number so at first glance is most likely not from an earlier car. Did you check the engine compartment plate to see if the engine is original? In other words the engine number on the block matches the engine number on the plate and the VIN on the plate matches the VIN on the dash and on the door jamb plate and on the firewall?

There's no engine number on the plate on a 78. My 5/78 buld date 280Z has L28 275875. The engines weren't sequentially installed but I guess that your engine might be from a ZX. What's the head type? (Letter and two numbers at the base of the head between cylinder one and two) and block type? (letter and two numbers on drivers side of block just behind the motor mount)

Edited February 23, 200916 yr by sblake01

Of all of the 280's entered by people in my online spreadsheet that's the biggest number so at first glance is most likely not from an earlier car. Did you check the engine compartment plate to see if the engine is original? In other words the engine number on the block matches the engine number on the plate and the VIN on the plate matches the VIN on the dash and on the door jamb plate and on the firewall?

Late 280Zs did not have the engine number on the engine compartment plate, so there's no way to check there. I think they stopped putting it on the plate after '76.

Late 280Zs did not have the engine number on the engine compartment plate, so there's no way to check there. I think they stopped putting it on the plate after '76.

Sorry, I didn't know that. I wonder why they stopped that practice?

I've seen a few early 77s with the engine number on the plate but it was definately gone sometime during the 77 model year as far as I can tell.

Thanks for the info. The number on the block is L28 353159

Of all of the 280's entered by people in my online spreadsheet that's the biggest number so at first glance is most likely not from an earlier car.

But it is also a bit lower than the earliest 280X listed there, so I think it's quite possible that it could be correct for a '78.

What Casting Number is on the block?

Blake - The head number is P79 and block is N42. Thanks again for all the input.