I have an early 74 260z, which is stock except for the dual Weber carbs. I am hoping to make this thing a reliable daily driver with a little extra get-up-and-go. My tentative plans are to put a 4-barrel intake from Arizona Z Cars, a Holley 390, and probably electronic ignition. I would like to see 180-200 hp. My questions are, 1:should I consider a head swap; 2:would I need anything else to get to my hp goal; 3:how difficult is installation of an elctronic ignition (I am a reasonably good garage mechanic). Any advice is welcome

 

go to www.hybridz,org they have the best site on engine mods and what not.

 

mild cam... header... ported head... minimum 3angle valve grind... mill head (for slightly higher CR)... electric water pump... electric radiator fan.... yada yada yada.

There's tons of options to make hp... take your pick.

 

you mentioned milling my head, how much is too much, or would I get better gains switching heads...and were can I get good info on porting my head, my background is as a machinist, so the work would be right up my alley, but I don't know a whole lot about what to port ( or should I just polish the thing smooth?) Also, do you know where I can get a good fan shroud for the 260z?

 

Just swapping to an electronic ignition as you indicated and the carb change over will not gain you the power you are looking for. In fact the 4bbl swap is likely to decrease your power! Do your homework on this before jumping in, there have been MANY, MANY, MANY discussions about this swap in the past on various Z sites and it seems that the majority is against it.

 

Porting the head & intake is (in my opinion) for the extremist. You will benefit slightly, but it's not one of the first mods you should do.

Mill the head .010 or .020. If you plan on hot-rodding it at all, I would advise getting a MLS headgasket.

Have you thought about using a 280zx radiator & fan shroud? I believe it will slide right in place w/ no or little tweaking of the shroud.

 

I agree. 4bbl carbs make me sick. Do a triple carb setup.

 

The 260 has a smaller bore than the 240. It has the same crank as the 280. The '74 E88 head has smaller water jackets to make it run hotter for smog. The carbs are nfg too. 4bbl. is a waste of money. Webers are mostly for racing. Realisticly the 260 will never make 200 hp. The ZX engines have bigger valves and you can do more with the money, drive the 260 while you are getting the real engine built right. Then drop it in. You will have a reliable car with lots of power. Good luck.

 

thanks for your help, if I were to build a ZX motor out of the car, I should be able to drop it right in, correct? Would dual SU's be a better option than my Webbers? The hp goal is secondary to an efficient, dependable daily driver...I also wanted to keep the car n/a (for the sake of simplicity). I had been considering the electric fan for some time, but if I were to add an electric water pump as well, would I need a higher output alternator?

 

If thats your concern then I would recommend going with a late ZX motor (81-83)and keeping the Fuel Injection that comes with it. Get all the wiring, electronics, and the ECU and just make the conversion. With the addition of a fuel pump and everything I just mentioned it's a bolt in swap. If you have to go with carbs then so be it, but there is a reason the entire automotive world made the swap to F.I. and it wasn't just about emissions You'll get more horsepower AND reliability right from the start.

Also the stock ZX alternator would handle both the electric fans and the electric water pump.

 

Programmable EFI is better than carbs but definitely not the bone-stock EFI setup. Often the decision has to to with available $$$'s! Programmable EFI is the ultimate but the cost is pretty high. A good set of tweaked SU's or 3x40DCOE Webers is way cheaper and way easy to set up and troubleshoot. I've been running the same set of 40's on my 240 (boredL28/E31) for 15 years with no problem. Bought 'em used for $300. I've rebuilt them twice, dead simple. I've toyed with the idea of upgrading everything to Electramotive/TWM EFI (My TWM 3x manifold can be modified for throttle bodies and injectors) but I can't justify the cost.
My other Z is also carbureted, a Rochester Quadrajet feeding a Rajay Turbocharger on top of a Chevy 350. I can only run about 10psi of boost on pump gas but that's enough to smoke 'em pretty good!

 

Please, before you do anything, go to motorbooks.com or call1 800 826 6600 and find their Datsun engine build books. I have also been told that Summit Racing has a CD Rom that you can buy and plug in what you want, and it will tell you what you need. That's 1 800 230 3030. But opinions are like bellybuttons, everybody has one so here's mine - fuel injection should be involved just for reliability.