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こんにちは, It's been a while since I have been on but we are finally in our new home and I have had some spare time to pull the z apart. So my question is, what would be the best build for a n42/n47 na set up? That's the block and head I have right now and I believe it shouldn't be a bad place to start. Any of you have experience with this build? I have read mountains on the n42 head but I can't find much on the n47. From the few things I have found some good ideas might be replacing the dished pistons for flat tops. From familiarity on the head I assume it would bring compression up to about a 10:1 and you would have to be crazy to not put a new cam in after that. (270 - 280 degrees on that cam, correct?) After that you would want your head matched up to your exhaust and intake for better flow. What else might you want to do? I currently am running round top SUs and the stock exhaust. The exhaust will be replaced for 2.5 and, if dreams come true, I will switch to some triples. What ideas can you folks dream up for this motor/head? I am not looking for any crazy power upgrade, just something to put a smile on my face. I wan't to make sure I can still daily it without putting racing fuel in it. Thank you in advance, the support I get from this forum by far makes it my go to place.

Is got 89mm Nissan KA24E pistons in it. They appear to be "reversed dome" style dished pistons. Also remember that here in California the highest octane fuel available is 91, and its got ethanol in it. While I only use the best (garbage) gas available it runs fine in day to day usage. I also told Dave that I prioritize daily driving over power so he may have chosen dished pistons to match that request. This thing makes plenty of power without flat tops so I have no regrets.

I don't think so because I've replaced the rubber hoses at each wheel. But I will make sure.

I bought a 2.5lb Kidde unit and mounted it behind the passenger seat by using a 5"x10" piece of 5mm thick black ABS plastic with 4 riv nuts placed to coincide with the fire extinguisher's bracket holes. I placed the ABS base under the carpet and secured it to the floor with 3M heavy duty double stick tape, replaced the carpet and put 4 bolts through the base and carpet into the riv nuts. Finally I placed the extinguisher into it's very secure base.

Nice. I'm not a fan of most painted valve covers, but I gotta admit... I like that one.

People report mixed results when raising the compression ratio by using flat top pistons. Apparently, fuel quality differs across the states so some people get knocking and others don't. If you don't shave the head the N42 or N47 gets you almost 10:1. http://www.ozdat.com/ozdatonline/enginedesign/ There are so many opinions out there it's crazy. Some people like the rumpety-rump cam noise, some like the 7500 RPM screamer, some like the torquey 3.1 liter engine. RM needs to decide what makes him smile, I'd say, and get those details.

If you could find a zx motor from a junkyard and use the flat top pistons and the p79 head you would be better off in my opinion. The n47 is the least desire able head there is. Google datsun z motor calculator and try different components. The n42 head would be able the first one with bigger valves already then the n47, then the better p79. Google " diseazed motor build classiczcars.com" or go to datsungarage.com and find the motor sub category and then the cylinder head mod. I can post those links in the morning as I have them bookmarked on my laptop.