Replacing exhaust manifold

[A1exander]

Hey guys! Recently bought a 76 280z. It was pretty clear the car had a bad exhaust leak, which I was hoping would be as simple as a gasket. Unfortunately after removing the manifold I discovered a crack. I can't seem to find replacement stock manifolds anywhere, and the few stock options I did see seemed to be around 650 dollars. The MSA 6-1 headers appear to work fine for around 230, But the shape seems off. They are longer with a different shaped flange at the end? My guess is that they connect under the cab rather than where the old manifold connected. Unfortunately the car is at a relatives until I can get it running again. I do not have the time nor money for a full exhaust system swap to the 2.5 pipes or anything like that. What exactly is required to replace this manifold?? HP/sound improvements are not necessary, yet definitely welcomed if the price is right. Any advice or knowledge about doing a direct bolt in replacement would be greatly appreciated. Thank you guys!

SIDENOTE: The manifold is N47, with round ports.

Edited April 1, 2014 by A1exander
forgot details

[Zed Head]

Curious to see the crack, if you could post a picture. I have a leak that seals up but was confident that I had sealing surfaces. I suspect that I also have a crack but won't know for sure until some future date.

There are five parts to the exhaust system - a pipe from the manifold to the anti-resonator, the anti-resonator (I'll call it the AR), the pipe from the AR to the muffler, the muffler , and the tail-pipe. The MSA pipe might connect to the AR or it might require custom piping. The guys at MSA will answer your questions if you call.

There's someone down here that has some MSA headers for sale (not me), although he says round-port when they should be square - Datsun Headers

Make sure that you know what type of head you have. Parts get swapped, and there are square ports and round ports to be aware of.

Edited April 1, 2014 by Zed Head

[Mark Maras]

Just checked PicNPul here in Portland. There is a 76 in SE P. & a 77 in Sherwood. I don't know if it's worth the drive. I'd be glad to drop by the SE P. one & see if the ex. manifold is still on it. I can also check Sherwood if SE P. doesn't have one.

[Zed Head]

Uh oh, we're stomping the same ground. I think that the 77 still has its manifold, although the transmission is gone. But it's actually a 78. It would have the round port manifold, which would cut the corners on his ports, if he has the 76 N42 head. I think that I've seen that 76 too, I have a vague memory of an old moldy car. I think that it still had its engine and parts. Maybe.

[A1exander]

Thanks for the replies guys! I suppose I can't quite check the heads, but the exhaust manifold that I took off is definitely the N47 with round ports. At the same time my mind is telling me if I am replacing it anyways, why not just get the headers? They would be brand new, and also sound better. Is there a reason going with used stock would be better?

[Zed Head]

A used exhaust manifold from PnP is ~$40. That's the main reason. You mentioned money in your first post.

[A1exander]

oh! okay well thank you I assumed it would be more. one last question, I just found an exhaust manifold on craigslist but it is the L28 ET turbo exhaust manifold, would that be compatible by chance? Only asking because it is local, if not I just may go the PnP route!

[A1exander]

Nevermind, dumb question. just looked it up, i'll have to call PnP.

[Jeff G 78]

Obviously, the head and/or manifold has been replaced as a '76 should have an N42 with square exhaust ports. Be sure to verify that the head is an N47. It's possible that a PO replaced only the manifold and used the wrong one. Assuming they were replaced together, you should be able to find a used replacement manifold. I've probably scrapped several of them over the years. I'm not sure if I have any in storage. The problem with rust belt cars is that the outlet studs tend to twist off.

[ZCurves]

Is Welding / Brazing an option???