JMortensen

Norm, if you only shim the towers up .060 do you run into issues with the wipe pattern? I'd rather buy another set of shims than have to mess with the lash pads. Nevermind, I just realized you're going to have to mess with the lash pads anyway, which would be the advantage to doing the P head instead.

Not addressed to me, but especially if you have an N47 or N42 hanging around, modding the P head is way easier than swapping pistons. Here's the details on the mods necessary (thank you Darrel for finding that site): http://www.geocities.com/zgarage2001/head.html You don't even need to mess with lash pads. Just use the longer N valves instead. Shimming the cam towers is the hardest part. That's 20 minutes worth of work.

Well it looks as though it is going to be very easy to drop the diff out. Why would you need to drop the frame out? Seems to me a lot of trouble to go to so that you can more easily remove the frame from the car. Plus, your tube is roughly 1x1x.120" or 25x25x3 I believe that would be in mm. So that can't be all that heavy. The 1x1 is 1.44 lbs/ft. I'd guess you have maybe 5 or 6 feet in the rear, plus whatever you do in the front, and the material to tie them together. I can't imagine this thing weighing more than 25 lbs when its all done. Doesn't seem like a big deal. Am I missing something?

I think if you put a splitter on the bottom of a urethane airdam you had better brace the bottom of the airdam. The splitter sticking out the front is going to increase the pressure at the nose of the airdam. I think the aluminum piece between the dam and the radiator is going to help, but I'd run a brace or two or three from the aluminum down to the back side of the splitter. With it braced like that, then if you hit a curb or a parking stone you'd still damage your brace, but not the airdam itself. PS-Note my rubber skirt on my airdam flapping under the car at ~110 mph in the sig pic...

Add one more to the QUENCH column!!! :D

That's the purpose of the quench area. With flat tops and a small chamber, when the flat top comes close to the flat head, it "squirts" the air/fuel into the chamber area, making it tumble and mix more evenly as it does so. You're basically talking about the same thing, but using the piston as part of the combustion chamber. Nothing wrong with that I suppose, two different ways to skin a cat.

Me too.

Still quite a bit more open than the E31, but closer for sure. I always thought the chamber shapes were pretty similar looking. One problem is that if Jessie went that far on shaving the head he wouldn't be able to run CA pump gas.

I don't think that changing the seats was the big deal. It was the combustion chamber shape. You have a pic of your combustion chamber Norm? I bet it looks a lot like an E31...

I'm running an ACT pressure plate with a stock disk, and I'm pushing 240whp according to the trap speed calculators. Works great, no complaints.

No clue on the swap meet, didn't know there was one, but I really think you did get swindled and I'd be sending that thing back and asking for my money back.

This is a never ending debate. You can search to find the detailed explanation, but bottom line is that I think that Stephen is right. That being said, lots of guys have made pretty good power with that head, without changing the combustion chamber. Dan Baldwin is making 255 whp with his stroker. I think Norm is using a pretty stock combustion chamber, cleaned up but not welded up. So the quench thing isn't the end of the story. You CAN still make good power with that head. The other cheap option is to get a P90 head, shave it .080 and then shim the cam towers up. It has the better quench area and if I were building another street L engine that's what I would do. Then you can run the N42 valves in the P90 head and get about 10:1 compression. There used to be a page called The Datsun Z Garage by Bryan Little, but I guess it's gone now. It had all the details on that head modification. If you were going to run race gas I'd say get the Maxima N47, which is like the P90 but with a smaller chamber so higher compression. The early E88 head is similar to the E31 I'm running right now. Compression is too high for pump gas with flat tops.

Something's not right. BTW, why not go with the 2mm gasket. Then you could peel off 3 .6mm gaskets.

There is a big *** hole there in the front, so I'd expect the pressure equalizes pretty fast. Not sure how much volume flows through the valve cover vent, since it has a pretty good baffle in there. I think the idea on the stock PCV setup is more to alleviate pressure to avoid oil leaks, not create vacuum for hp gains.

Maybe it's time to put down the sliderule and get your hands dirty again...

Jeez Dan, how long has it been since you've had an L apart? Follow that "space between the front of the block and the timing cover" to the bottom. The bottom of the timing cover seals to the oilpan, and the space, aka big ol' hole, continues straight into the crankcase area.

I'm not following. What is the end result going to look like? Seems like you could have gotten some 4" wide 1/8" plate and not had to weld anything, or am I missing something?

Really? What about that big ol' hole in the front there where the timing chain goes. No pressure gets through that big hole? I agree that the crank vent is the one that should get vacuum if one of them is going to, but to say that the valve cover vent is TOTALLY unrelated is false IMO.

You've got 4 gears to get the slack out of when you're turning one wheel and looking for the other to turn, so it will take a bit of rotation. If you measure backlash at the ring gear (took the cover off and grabbed the ring gear itself and felt the play between it and the pinion) it would be a lot less than you get when you twist the pinion. There are some diffs where you have to set the backlash with pinion rotation, and I don't have a specific example, but it might be 1/8" of twist on the pinion to equal .012" backlash. It's not at all a 1:1 ratio. What you've got there sounds normal to me.

If you have showy rims, make sure they put weights on both sides of the rim. Balancing with weights only on the inside is nicer looking, but it is a "static" balance, vs a "dynamic" with weights on both sides. Dynamic is the way to go. If you don't have a lip on the outside edge of the rim then the shop should use the stick on weights as close to the outside edge as possible.

I bet the mustache bar and this subframe weigh about the same. Rob, that thing is REALLY impressive. It's coming together very nicely, congratulations.

My wife and I spent a night there on our honeymoon. Got to the rim at dusk. It was so beautiful she actually cried. We stayed in Williams at an old whore house. Then we went back the next day and did a helicopter tour. We went in mid-April and there was nobody there. I hope its a similar situation for you and your family. We were the only ones on the helicopter tour, which was very nice. I wish they still took the choppers down into the canyon, but still the visit to AZ was definitely better than the other part of the honeymoon spent in Vegas!!! Oh, forgot to mention that we ate at... get this... Pancho McGillicutty's in Williams. Pancho... McGillicutty's...

Stock Datsun EFI sucks big time. Worst part is when you get the neo-purists saying that EFI rules and carbs sucks, and they're talking about 1978 Datsun EFI. Some people's children!

Those are the Victoria British or now Black Dragon flares. Rumor has it they're actually cut down VW bug flares. Do a search on that and you'll find pics of an orange Z that looks similar but flares are wider.

Suspension Techniques.