If you have a '77 5 speed you might. I did. Install it before you put the motor back in and it'll be apparent if it touches.

My 280 with 16s doesn't rub at all. The rear crossmember is bigger cutout is bigger too. That lets more pipe tucking up. My 240s is smaller. The 2.5 won't fit up in there as far and rubs very rarely. I can stop it but sometimes forget. Also it's lowered a touch with 15s and lower sidewall tires. I suppose the OE 240 exhaust diameter is smaller than a 280s? You won't have any problems. You'll most likely need a $20 resonator installed but mine sounds even better with that thing. It was too loud.

You see, that's where it will scrape. The lowest point is where the straight pipe goes under the rear crossmember on my cars. If I had those bolt together flanges removed and then straight welded it wouldn't do it. 

I'm almost positive the header flange is even with if not higher than the oil pan. Pictures later...

You see, that's where it will scrape. The lowest point is where the straight pipe goes under the rear crossmember on my cars. If I had those bolt together flanges removed and then straight welded it wouldn't do it. 
I'm almost positive the header flange is even with if not higher than the oil pan. Pictures later...

Okay Cliff, you’ve given me the confidence this 6-1 will work. I didn’t know the 240z tunnel was smaller. That makes sense as the posts I read were referring to the 240z. Wouldn’t expect they’d be different but learned something new.
Gonna order the ceramic coated 6-1. The MSA website state a difference between 1976-1978 280z and the ZX
One. Both have round ports so it appears the only difference is the ZX has a spot for the 02 sensor. I should be good with the 280z version on my P79 I assume.


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The good thing about the o2 bung is the possibility of future programmable EFI.  

The good thing about the o2 bung is the possibility of future programmable EFI.  

Oh geez.....hard to think of the future when I just what it on the road. It’s like $30 more


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Walker Exhaust 1 in. o.d. x 0.5 in. thick, 12 mm. thread stainless steel sensor bung

 

 

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But if the headers coated, welding a bung in compromises that...

12 hours ago, Av8ferg said:

Okay Cliff, you’ve given me the confidence this 6-1 will work. I didn’t know the 240z tunnel was smaller. That makes sense as the posts I read were referring to the 240z. Wouldn’t expect they’d be different but learned something new.
Gonna order the ceramic coated 6-1. The MSA website state a difference between 1976-1978 280z and the ZX
One. Both have round ports so it appears the only difference is the ZX has a spot for the 02 sensor. I should be good with the 280z version on my P79 I assume.


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You will really like the header at least I do.  I put them on both my Zs and the heat reduction in the engine bay is incredible.  With that header your fuel rail will feel cool to the touch after running the car.

Here's my 280's motor before I put it in.

 

Go to Harbor freight and get an load leveler.  With one of those you can do it by yourself.  I needed a little push to do it though, it's intimidating having that big of a thing hanging over your car.  Thanks to Jeff G 78 and RossiZ again for the "push".

 

You will really like the header at least I do.  I put them on both my Zs and the heat reduction in the engine bay is incredible.  With that header your fuel rail will feel cool to the touch after running the car.
Here's my 280's motor before I put it in.

 
Go to Harbor freight and get an load leveler.  With one of those you can do it by yourself.  I needed a little push to do it though, it's intimidating having that big of a thing hanging over your car.  Thanks to Jeff G 78 and RossiZ again for the "push".
 

Looks good Cliff! So I noticed you made a custom cutout for one of the heat shields? With the coated headers has it mitigated the L28 hot start problems these cars have. My ZX engine came with that odd over the valve cover blower which I have no intention of putting back on. I was considering putting an adhesive heat shield tape under the metal stock heat shield to slow the heat transfer a bit but if these coated headers really reduce the heat maybe its not required. I’m going without the bung on the headers. Does everyone agree they should fit in the P79 just like the N47 head?


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Yes, the header for a '77 N47 is what you need with that P79.  I've never had a hot restart problem that I can remember, even back in the '80s when I first had a Z.  Soooo with these headers you definitely will not especially with your aluminum fuel rail. 

Yes, the header for a '77 N47 is what you need with that P79.  I've never had a hot restart problem that I can remember, even back in the '80s when I first had a Z.  Soooo with these headers you definitely will not especially with your aluminum fuel rail. 

Great, thanks!
I still need to make a few adjustments to my custom rail (copy of yours). The Rail came 24” which is too long. I need to cut it down to about 21” and retap the ends.



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Yep, mine is 21" too.

The header is a little lower than the oil pan but not as low as the bottom of the frame rails under the doors.