Hey guys I have a 77 280z and I was wondering what is the highest compression ratio that can be run with the stock efi system? 
 

looked online there is a lot of information but nothing specific to the stock efi that I’ve seen. 

I am still wondering on how you will pass emissions with all these changes?

I had a rotted out egr tunnel on my '77. There was a recall and you should find a sticker under the hood on the passenger's side if it was done. Mine was not and caused a huge vacuum leak. I got the Z for $1,400. Put a N42 non egr intake on and it runs fine.

Here's my rotted out egr where it connected to the tunnel. I tried to sawz-all it off and have it welded up but my welder suggested a replacement. It was much cheaper than him building up that hole.

 

Your's looks very similer.

 

 

3 minutes ago, siteunseen said:

Your's looks very similer.

 

 

I think I’m just going to chop it off and weld a plate in 

This is from Wick Humble's book. Chapter 11, tech bulletins and recalls. Page 194.

2 minutes ago, 280zdude said:

I think I’m just going to chop it off and weld a plate in 

If you dont have to have an egr I'd try and find an N42 intake manilfold and delete all the crap.

5 hours ago, Patcon said:

I am still wondering on how you will pass emissions with all these changes?

He won't if the person doing the visual knows what to look for. That's the problem with California. You could modify a car to put out only carbon dioxide and water vapor, but if it doesn't have the factory parts, you fail emissions.

Frankly, @280zdude could install a MS with an O2 sensor and tune it to have better tailpipe emissions, but he couldn't pass CA emissions because MS isn't CARB certified.

2 hours ago, SteveJ said:

He won't if the person doing the visual knows what to look for. That's the problem with California. You could modify a car to put out only carbon dioxide and water vapor, but if it doesn't have the factory parts, you fail emissions.

Frankly, @280zdude could install a MS with an O2 sensor and tune it to have better tailpipe emissions, but he couldn't pass CA emissions because MS isn't CARB certified.

I have a work around that I’m just thinking it won’t pass the dyno test... does it really make that big of a difference? 

11 minutes ago, 280zdude said:

I have a work around that I’m just thinking it won’t pass the dyno test... does it really make that big of a difference? 

My question is does taking the egr out affect the emissions test. Not visual.. how does it affect it and if you run 91 octane will it run better maybe a high flow cat? 

The purpose of the EGR is to reduce NOx. Octane won't affect that. A good cat might.

Another question should I replace the head gasket as a maintenance item or should it be ok? I have almost everything off and I’m replacing the timing chain and all the gaskets around the car..  

10 hours ago, 280zdude said:

I’m replacing the timing chain and all the gaskets around the car..  

If your headgasket is old ofcourse put a new one on, your doing all the gaskets but not the most important one? 😟

I read that there are people that reuse a headgasket???  After i take apart a engine i ALWAYS use a new headgasket..  I think that is the only way to go..