bradyzq

One reason I don't use the "chokes" on my triples (Weber 40DCOE-18) is that they pull to the front of the car, whereas the SU choke cables pull to the back. That and the pump-the-gas-pedal-a-few-times method works fine. There is a HUGE thread on triples over on hybridz.org too.

IMO, we should be thankful that if a part becomes NLA, it should be a non-essential aftermarket "performance" muffler. Sure the vertical dual tip is cool, but it's not stock, unless you have a 432, and that's a different setup anyways... The rest of the exhaust system for 240's is pretty much the simplest design out there. Any muffler shop should be able to make one easily, at a reasonable cost. Does any lament the loss of the "Mulholland" suspension package? Not likely because there are other options that do the trick just fine. I think this is a valid comparison.

This should work: http://store.summitracing.com/partdetail.asp?autofilter=1&part=HLY-12-804&N=700+115&autoview=sku

Nope, that won't work. I doubt that you could get accurate adjustability at the low pressure you need. Also, that is for a return type system.

I would suggest #2 ish. Tank => filter => pump => filter => carbs => FPR => return

I strongly suggest that you get your car on a good dyno, and find out what your air/fuel ratios are. It will also give you a chance to dial in the timing. You may even be fine with 34's. There is a lot of mis-information out in the world regarding Webers, but the dyno doesn't lie. Another good idea, IMO, is to get a wide-band O2 sensor with logging ability, and drive with that for awhile. They're not that expensive and are very much worth it.

I'm with you on the hibernation thing. Maybe I'll see my Z in May..... You're welcome!

Still on the carburation of your de-stroked L28, I still think you'll be pretty close with the 40's. Here's why: The stock Weber kit for 240Z came with 40DCOE18's with 28 main chokes. If someone can find their Pat Braden book on Weber carbs (which I can't at the moment), it'll be listed at the back with all the kits. And it's the chokes that really determine how much air can flow. And air flow is proportional to cross-sectional area, soooo 28's for a stock 240 means 29's for a stock 260. You can go all the way to 36's on 40DCOE's. That would represent a 54% increase in airflow over 29's, which would be the "stock" starting point. So, if your engine is making more than 54% more power than a "stock" 260, then you'll have to look at 45's.

If your speedo was already off, here's how to calculate another way. And it's probably a good idea to try this out anyways. Head out on the highway where there are mile markers. Drive an indicated 60MPH, which is 1 MPM (mile per minute) for exactly 2 miles. Time the amount of time (we'll call it T) it takes to cover those 2 miles in seconds. Your actual speed in MPM is 120/T. So, take your existing speedo gear tooth count T/120. Teeth(needed) = Teeth(actual) x T/120

According to my calculations, you effectively have a 4.265:1 rear diff, taking your tire size into account. That's a 3.7% difference from 4.11:1, which means you'd be closer with a 21 tooth gear (pn 32703-86401). Of course, all this assumes your speedo was accurate before you changed wheel/tire combo and diff!

If you're not using stock diameter tires, now is your chance to include that difference in your calculations too.

When you re-attach the head, you WILL be using new hardware, right? Ideally, use head studs, especially if you don't find someone to check your head for straightness. You can torque the head down tighter with the studs than you can with head bolts. They're only a bit more expensive than head bolts. Summit sells a kit for $135. http://store.summitracing.com/partdetail.asp?part=ARP%2D202%2D4206&autoview=sku I had suspect compression in neighouring cylinders on a 5 cylinder Audi motor of mine. On the Audi, like the Datsun, the head bolts are stretch bolts. In theory, single use. So, with the head still attached, out came the old bolts, and in went the head studs, which can safely be torqued down more tightly. I took another compression test, and I had regained the lost compression. In my case it was a band-aid temporary solution til the head comes off. In your situation, it could straighten out a _slightly_ warped head, and, if you can find a competent machine shop to check your head, you will have done it completely right, with the best chances for long life!

BTW, how high do you intend to rev? I think your cam's power band should start tapering around 7000RPM or so.

Theoretical question here about Webers: Since 40's, 42's, 45's, etc., all use the same jets, shouldn't you have the same capacity to draw fuel with all DCOE's? With the smaller venturis of the 40's, and therefore higher air speed, you're certainly getting a strong enough "signal" with which to draw the fuel. So, it appears that you might actually run out of AIR, not fuel. Which means that, instead of leaning out at the top end, you may actually go too rich. All this to say that with an upper limit of 36 main venturis (biggest available on 40DCOE I think), you may be ok. Any holes in this logic? Cheers,

So, to nit-pick, it seems I have the earliest ZX-only 5-speed. If I was grasping at straws, I would say the 79 box is actually a 280Z tranny!