Exhaust manifold difference?

[Dyst]

Hi,

I am looking into purchasing an exhaust manifold for my 1975 280z, but the one I want says "1977-1978 Datsun 280Z (2.8L Non-Turbo)
1979-1983 Datsun 280ZX (2.8L Non-Turbo)
Fits Non-Turbo Models with 2.8L L28E SOHC I6 Engines Only" in the description

I asked if it would fit and they said the bolt holes wight be different.

Wouldn't it be the same across the years? I've heard of people using 280zx turbo manifolds on n/a 280z blocks.

Any input would be greatly appreciated, thanks

 

[chris frizzell]

Hi i have a 1975 280z and had the same question . get in touch with Sean on here or through z story i have one of his systems and there top quality or he may point you in the right direction . Chris

 

[jonbills]

the stud postitions on the heads are all the same, but some years the exhaust ports are square and some years they're round and manifolds differ accordingly.
Square port manifolds are ok on round port heads, but round port manifolds are no good for square port heads.
280z and 280zx bodies are different, so you also want to be sure the manifold will fit whatever system you intend to use.
Which head do you have? it'll be cast on it on the spark plug side.
n42 or n47 or p79 or...

 

[SeanDezart]

A 1975 head should ba an N42 unless it was swapped during its' life.

You're looking at an ebay item (with the moist useless gasket on sale today) and the people selling it clearly don't know Zs....at all or they would change their listing for starters so don't count upon them for any clear advice.

The good news is that you've come to the right place for advice although I'd differ from Jonbills and say that you CAN use a round-ported header with a square-ported head.

If you then want to improve performance, you should look to enlarge the manifolds' ports so as to at least be wider than the heads' exhaust ports and/or enlarge the heads' ports to match those of the exhaust manifold. Either way, to optimise engine performance, the exhaust ports should at least match !

Lastly, an engines' performance is due to everything working together in harmony - it is NOT a result of parts merely fitted together - my last advice is to have a clear goal of what you want from the outset and choose accordingly and not by opportunity.

 

[jonbills]

The good news is that you've come to the right place for advice although I'd differ from Jonbills and say that you CAN use a round-ported header with a square-ported head.

You can fit square headers to round ports and open up the flange metal some but the other way around don't cut it

! It's dishonest, worse - it's ignorant....from a 'specialist'

And I thought I was quoting the expert!

https://zclub.net/community/index.p...ader-for-square-ported-engines-en-ebay.24578/

 

[Dyst]

Thank you all very much for your input, would anyone have a link to Sean's exhaust manifold? I'm not too fussed about the power, I plan in having a custom exhaust system welded on after the manifold, so not a bug deal if it doesn't fit the z body the best, also I'm trying to remove the ugly/rusty stuff from the car lol, except the paint, I like that how it Is for now xD

 

[jonbills]

Thank you all very much for your input, would anyone have a link to Sean's exhaust manifold? I'm not too fussed about the power, I plan in having a custom exhaust system welded on after the manifold, so not a bug deal if it doesn't fit the z body the best, also I'm trying to remove the ugly/rusty stuff from the car lol, except the paint, I like that how it Is for now xD

search zstory exhaust on Google is probably easiest.