Another NA ZX question...
 

I am planning on keeping my 79'ZX naturally aspirated, and the engine is finally about to give out. It's just the valve seats, they are leaking, so I need to finally bring the car up on blocks to get them replaced, and I was going to do a few more things while I was at it. Can I use the N42 head on my car, even though it's not one of the 80's models? Also, does any specific company make piston kits and such for a little more power? I plan on finding something to tweak the ecu, but I haven't been able to find anything so far. I am going to add a 60mm throttle body, and a new air intake and exhaust while the car is up. I would really like my Z to go 0-60 somewhere under 6 seconds. I have seen a few na cars get there, and if y'all could tell me how it was done I would be really appreciative. Well, like I said. I did use the search function, it just didn't really give me what I was looking for. Thanks again for all the help in the past.

You can use an N42 head. I would find an 81-83 ZX engine with flat tops and rebuild that and use it. The extra compression will help. Get a mild cam, add a header and nice mandrel bent exhaust to go with the other mod's you listed. Lightening the flywheel would help too.

Also make sure you have 3.90's in the diff or pick up some 4.11's I see them for sale alot.

yes you can use a N42 head on your block it should just fit right in.. if you want to get a lil more HP out of your engine your on the right track.. id get head work done.. get it port and polished. and get a performance cam too.. id get a mild one so your idle wont be so rough. and id prolly get some headers for that car as well.. Even with just porting and polishing your heads and adding some headers youll notice the difference right away.. i dont know if youll be able to find anything for your ECU i dont think theres much you can do for that. you prolly wont need to do anything on that since your car is a n/a model..

Basically you have dished pistons and you can rebuild your head and install later 280zx flat top pistons for more compression. If you put a performance cam in your engine, the higher compression is recommended. That will give you more power over the entire rpm range.

If you grab the whole block and head from a 81-83 ZX then maybe shaving the head will be good for extra compression. Be sure to put a new timing chain in and advance it to the #2 position with your performance cam in place. The 4.11 rear will really help your 0-60 time a lot!

I do not recomend Motorsport Auto's 60mm throttle. it is very sticky and the idle settings are not all that good. My idle varies and the throttle response for low speeds is too sticky and sensative. Try a 240SX throttle body with the spacer. In addition to the 60mm throttle, port out the intake manifold a bit to match the throttle opening. A larger air flow meter modification will also be good as that will be your bottleneck on the intake if you leave the stock one in place. You can get a 280zx turbo AFM and carefully remove the electronics inside and isntall electronics from a non-turbo AFM. (maybe the one you have now) Tune it a bit. With the longer duration cam, your engine will actually be getting a bit more air inside and you can use more fuel. The AFM is a good point to tune the computer to richen up the mixture.

This is new info to me, but I heard a guy say he used a mid 80's BMW 325i AFM . Its larger than the 280ZX turbo AFM by a bit, and the same Bosh fuel injection system that the Z has. It is also already programed for an N/A application and has the exact same plug on the bottom! It will need to be modifed to richen it up, but that's easy. They are on a 2.5L straight six.

Top End does the BMW AFM mod, and they can set you up with one ready to go I believe.

What does it require to get one ready to go? Turn the flap adjustment screw 3 notches?