Hi:

We are working on a family '74 260Z project, and finally about to pull the L28 engine with the cracked block out of the car and replace it with another L28. The donor engine had fuel injection, but we are going to replace it with the dual-SU carb setup from the old engine. Someone told me a while back to use a specific set of manifold gaskets in this swap, and I feel like they said it was from an earlier engine, but I have now lost that piece of advice and just wanting to hear from some of you folks who know better than me before I order anything.

Check this short video?

Thanks in advance!
Michael
Project Z ICT

Look between 1st and 2nd spark plugs to see what head you have. Should be an E88 or N42, maybe N47? That will tell us what exhaust port shape you have and whether or not you have the injector notches. If it's an E88 you can use the 240 gasket. Fel-Pro has a universal diamond shape exhaust manifold gasket but it has the injector notches too. From what I remember it will work with carbs but I've never used one so maybe someone can tell us? If it's the OE E88 I would use the right gasket with round intake holes and square exhaust ports. I bought mine through Nissan dealership but zcardepot.com has them too.

Here's a good read on what you're doing. You might read something helpful.

@siteunseen THANK YOU! This is the kind of info I was looking for. Much obliged.

Im curious, is your engine really an L28 or are you just using shorthand. I ask because my block is strictly an L28 and I cant figure out where it came from. Near as I can tell, that engine wasnt in the US market

26 minutes ago, nowak1981 said:

Im curious, is your engine really an L28 or are you just using shorthand. I ask because my block is strictly an L28 and I cant figure out where it came from. Near as I can tell, that engine wasnt in the US market

To be honest I have assumed that was just what this 2.8L Nissan block was called generically, if I am wrong I would love to be set right so I know better in the future. I have spent 40 years wrenching on old cars but almost none of them have been Japanese so it's a whole new world of nomenclature to me.

have you looked at the stamp on the side of the block? its looks like this. It can be hard to see, I had to remove something to get my phone in there.

On 11/20/2025 at 10:54 AM, DadAndLadZ said:

'74 260Z project, and finally about to pull the L28 engine

A 260Z should have an L26. Might be where the question comes from.

That pic is from a RHD 240 or 260 most probably a 240.

@nowak1981 Here are pics of both the blocks in our possession. The top one (blue) is the one we are pulling; the bottom is the "new" engine we are about to swap in. Both are from later 280Z models.

@Zed Head Yes, I should have been clearer. This 260Z has a later 280Z engine in it already. We are taking that one out and replacing it with another 280Z engine. My main concern is that I plan to bolt the dual-carb intake manifold up to the fuel-injection heads on the "new" engine, and I was basically just hoping a) that will it work with the flange from the intake covering the injector holes which are not present in the carb-intake head; and b) that someone in here could point me to the correct gasket.

Well, here is the AI generated answer:

"When swapping a 280Z L28E intake manifold for one used with twin SU carburetors, such as the 240Z manifold, the correct intake/exhaust manifold gasket to use is the one designed for the carbureted 240Z/260Z models from 1970–1974. This is because the 280Z L28E manifold is designed for fuel injection and features notches for injectors, while the SU carburetor setup requires a gasket without these notches to prevent air leaks. Using an EFI-specific gasket with a carbureted manifold can result in air leaks and poor engine performance, as the gasket's sealing surface does not align properly with the carburetor ports. The 240Z/260Z gasket matches the round intake ports and square exhaust ports typical of carbureted setups and is recommended for compatibility and sealing integrity. Additionally, if headers are used, stepped washers may be necessary to ensure even clamping force between the manifold and cylinder head, especially when the flange thicknesses differ."

I would have said use the gasket that matches the head (and thus the injector notches) but I don't have a 240Z intake to test that on... Or a 240Z gasket to check on an L28E head.

Something funny. I got in to Rockauto to eyeball some gaskets, and one of the gaskets that AJUSA (don't know who they are) sells in the carb'ed 1972 section has injector cutouts. Maybe Rockauto just made a mistake.

One other thing I notice is that the intake port size is smaller for the carb gasket. Don't know if it blocks flow on an L28 EFI head or not. Something to look out for.

https://www.rockauto.com/en/catalog/nissan,1972,240z,2.4l+l6,1209169,engine,intake+&+exhaust+manifold+gasket+set,10220