Trying to put together a car for a junker endurance race. I need the drivetrain "Big Brains' to tell me which head to use. I have a N42 L28 Block in decent shape. It does have dished pistons which are different than the ones that were on my L24. Best I can tell this is normal. I have 3 Different heads in a shipping container that rats are currently pooping on I can use for this block.

I have an N42 head that came on the block. Probably needs some machining which is fine though I am not supposed to spend money on the car but I will.

I have an E88 with no camshaft installed. 

I also have a new or rebuilt P90 that is all wrapped up in plastic. 

I have absolutely NO idea what the difference in the heads are other than the P90 I think is used for Turbo setup which this IS NOT. 

This may be better suited for the Hybrid Z site but I am not a member there currently. I have ZERO aspirations for increased horsepower or any performance upgrades.....Just hoping it will make it through 2 days of running hard for the better part of 12 hours total. What would someone with way more knowledge of these block/head combos pick? 

Running the stock Fuel Injection. Its going into an 83 ZX. 

 

Carbs or EFI?  I don't think that the P90 will take carbs.  The N42 will.  The P90 will give lower CR than the N42, 7.4 versus 8.3, but should run fine, just low on power.

The N42 looks like the most straightforward choice.  Plus the camshaft should already be broken in.  

EFI. Yeah, I think I’ll just send that N42 head out to get flattened or whatever it needs. Old junk parts you have no idea if it’s already been shaved before…or at least I don’t!!

Don't let your rocker arms and lash pads get mixed up.  Take em off and label them and put them right back where they came from.  Others know more, but there are many ways to go wrong...

You can kind of guess by looking at original heads ID stamp. The uncut ones will have about a 1/16" space between the lettering and the head's bottom deck. If it's been cut the lettering is right at the bottom.

 

All those heads should be drilled for carbs . N42 is your best bet for dished pistons . 
 

Thanks guys. 

12 hours ago, Clay C said:

Old junk parts you have no idea if it’s already been shaved before

I've measured a couple stock heads and the original thickness of the N47, the P79, and the P90 is 108 mm (4.255 in). You can use that 108 mm measurement to determine if a head has been cut previously or not.

I haven't measured the other head varieties (because I haven't had them pass through my hands) so I cannot tell you what the others are, but I suspect they are all the same.

8 hours ago, madkaw said:

All those heads should be drilled for carbs . N42 is your best bet for dished pistons . 
 

My mistake.  Seems odd that a turbo head would be drilled for carbs though.  I thought the holes were different.   Maybe I was thinking of the non-US market N42 heads that aren't notched for EFI.   Oh well.  I've never had a carb'ed Z.

Good read here...

And some more...

 

 

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On 7/7/2022 at 6:05 PM, Clay C said:

EFI. Yeah, I think I’ll just send that N42 head out to get flattened or whatever it needs. Old junk parts you have no idea if it’s already been shaved before…or at least I don’t!!

Don't run EFI.  Get yourself a set of SU's.  The EFI will make for a very slow race car and will not like any engine mods.  Since you are in GA, contact a friend of mine that lives near Atlanta.  He has endurance raced Datsuns and has a huge stash of parts.  He has since given up on Datsuns and switched to BMW's since they simply are no longer competitive in ChampCar or WRL.  LeMons is possible with a Z, but you will still be slow.  PM me for his contact info.

My biggest issue with running a Z is that you will have more money in it than most other cars and if it gets wrecked, you will not find a cheap shell to rebuild it.  I built mine when they were cheap, but after a decade or so, the Z prices had gone through the roof and it was very risky to race it.  If you start with a car you already own, plan on spending at least $8k to get it on the track.  I had way more than that in mine and I had 30 years worth of Datsun hoarding before I started my build.  My car was done as cheap as possible!

Need a little knowledge on the Ignition setup. The car is running pretty good, after the above advice I went with SU's. Right now I am running an older distributer with points. I have a dist from a 76' that's electronic. It looks like the picture below. I dont have the black box on the end of the wires. I assume there is always some kind of module for the electronic distributors (dont think that is what that is). What else do I need to use this setup instead of the one with the points? 

All I have now is a coil.