74_5.0L_Z

I assume there is a question in there somewhere... So, what is the spring rate and free length of your springs? How much travel do you have available from your nominal ride height to when you either bottom the strut or stack the coils of your springs. If you run soft springs, then you have to have lots of available travel. Otherwise you will either bottom out the strut or stack the spring. In either case, the lower spring support will take some serious abuse and is likely to fail. I have had the same Ground Control coil-overs on my car for about 15 years. I have thousands of street miles on the car, hundreds of autocross events, and several track days with no issues. The key to a correctly functioning coil-over system is making sure that your suspension doesn't bind or bottom out during use (ever).

That carburetor is way too big for that engine. A 600 cfm would work much better. How is the engine mounted in the car? Is it mounted solidly using a mid plate sandwiched between the bell-housing and block? If the engine is not mounted solid, then that alternator mounting could cause problems when the engine moves around during acceleration. The exposed flex plate for the transmission shouldn't be a problem, but I would make some kind of cover. You do need a transmission cooler of some sort, or you will burn up that transmission on the street. This was obviously someone's drag race car, so they didn't worry about transmission heat. I have a T5 in my SBF (331 stroker) powered car. I use a Tilton hydraulic throw out bearing and 7/8 clutch master cylinder. If you look back at some of my older posts, I provide details of the installation.

I have Borla Pro XS mufflers on mine. I love the way they sound. They are mellow at part throttle but scream at full throttle. I've had people say that they don't mind getting passed by me because they love the way my car sounds.

There are several threads already regarding the building of roll cages. I will tell you that no one makes a roll cage that you can purchase that fits properly. If you want it done right, you are going to have to find a good race car chassis fabricator or do it yourself. I can pretty much guarantee that the cage at the link you provided will be junk.

It would be more meaningful to compare the racks based on the rack movement per revolution of the pinion. For instance the 240Z rack moves 1.81 inches per revolution,and the later 260Z and 280Z racks moved 1.59 inches per revolution. I like the idea of power steering, but I also want a rack that is shorter than the S30 rack (center to center of inner tie rod pivot points).

The threaded bracket is for the factory exhaust hanger.

That is much better Where did you get those clevises?

They are just pressed on. Just twist them while you pull and they will slide off. If you still have trouble removing them, then use the rack housing to push them off. To do so, you could place a clamp collar around the shaft between the rack stop and the end of the housing and then turn the pinion to push the rack stop off. Another option would be to remove the pinion so that the rack shaft is free to float in the housing and use the housing like a slide hammer to drive the rack stop off.

The cross member is the same but the rack bushings are different. The 280Z bushings are wider and the one nearest the pinion is contoured a bit differently.

It think that the rack in your car has been replaced with a unit from a later S30 (260Z or 280Z). The factory racks from a 240Z would have an aluminum pinion housing.

No problems at all, but I am running 23 inch tall tires (275/35/15 Hoosiers, 240/600/15 or 23.0 x 10.5 -15 Avons). You are more likely to have problems in the front with larger diameter tires. The issue that you will encounter with high backspace and large diameter on the front is rubbing of the tire on the T/C rod or frame at high turn angles. I used to run 245/45/16 tires (24.7 diameter) with the 5 inch backspace and had rubbing issues. I coped by limiting rack travel with the larger diameter tires.

With coil-overs, you can run 5.0 inches of backspacing all around without spacers using 15 inch wheels. You will have more space between the tire/wheel and the strut on the rear than on the front. On the front you will have about 1/8 inch clearance and on the rear you will have about 5/8 inch clearance. I wanted to tuck my rear tire in a bit more in the rear, so I opted to go with 5.25" back space and use a spacer on the front wheels. I have the SubtleZ fenders and quarter panels on my car and the 15x10 barely fit under the fender and quarter lips. The advertised clearance for the SubtleZ kit is 1.5 inches more than stock (I believe). The 280YZ kit advertised clearance is 3.5 inches more that stock (If memory serves). Therefore, the 15 x 12 should fit all around with 5 inches of backspace. I would err on the side of caution and purchase the wheels with a little extra backspace (say 5.25 or 5.375 inches) and plan on adding spacers as required. If you have too much backspace then you can add spacers to fix it. If you don't have sufficient backspace then you have problems that cannot be fixed cheaply. If you go to a 17 inch wheel, you can run a little more back space than with a 15 inch wheel. How much more I cannot say because I have not run 17 inch wheels.

I have a couple of comments: First, Have you considered lowering the differential by flipping the poly bushing in the mustache bar or by adding a spacer between the mustache bar and the frame. I have the differential in my car lowered by about 1/2" using washers above the mustache bar. Second, how do you like the TTT Drop Mounts? Are they aluminum? I am contemplating getting either the TTT or the ArizonaZCar drop mounts.

Is this only a problem on the 240Z? I've had two 260Z and have never noticed the firewall flexing.

I would like to see pictures of the tubular ARB set-ups installed on the Z and ZX cars. I would also like to see the details (tube OD, ID, length, arm length, bend angle, mounting).

I've been looking into this a bit as well. http://1speedway.com/index.php?route=product/product&path=76&product_id=90

I think we are on the same page. I just misunderstood your intention initially. I am watching your build with interest, and wishing I had the time and energy to do another ground up build.

My pet peeve is the frame rails hanging below the stock floor. At ride height I have less than 2.5" of clearance (ground to frame rails). So my frame limits how low I can set the car. For reference, I have about 3.5 inches of clearance between the ground and the bottom of the front cross member which is approximately in line with the floor pan. I autocross and run track days, so the lower the better as long as the suspension geometry is correct and nothing scrapes the track. If the frame rails didn't hang down, I would feel comfortable lowering the car an additional inch. If the floor, cross member, and engine were raised, then I would lower the car even further. If I were starting with a clean slate like you, I would build everything around the desired ride height. As with everything I've done to my car, I would do it differently if I did it again.

Are you planning to have the floor pan lower than stock relative to the bottom of the rocker panels? If so, why? If I were to redo the chassis on my own car, I would do the following: 1. Relocate the frame rails outboard and adjacent to the rocker panels (instead of following the path of the stock floor supports). 2. Move the driver seat, steering column, and pedals inboard a few inches. This will provide additional head room for the halo bar, provide more space between the driver and the cage for a side impact, and improve the left-right weight distribution. 3. Raise the floor as high as possible (even with bottom of rocker panels) provided that head height is not an issue. I love my car, but would love it more if I had made the design decision stated above. If I redo mine again in the future, I will do as stated. I hate the way my frame rails hang below the rockers. BTW, I am 6'0 but have a long torso (I have the legs of someone who is 5'6" but the torso of someone who is 6"5". Head clearance is an issue.

What oil are you using in the dampers on the carbs? Did you verify that the floats are set correctly? Float level is critical for these carbs. You do have the springs installed that hold the piston in the down position right? The clicking sound you describe sounds like uncontrolled movement of the piston inside the SU carburetor. This would occur if the springs were missing. Also, the oil inside the SU acts to damper the movement of the piston. At idle, the butterfly is nearly closed and airflow through the carburetor is low. Thus the pressure differential across the piston is low. This allows the mass of the piston and the force of the spring to keep the piston low. When the piston is low the needle restricts fuel flow to control the air fuel mixture. When you open the throttle, the air flow through the carb increases and the pressure at the venturi decreases as the velocity increases. This pressure decrease causes the piston try and rise. The piston will rise until the force provided by the spring and the mass of the piston is in balance with the force on the piston cause by the pressure differential. The piston should rise and fall smoothly as the throttle is opened and closed. If the spring is missing, then the piston will slam upward and downward making your clicking sound. If the oil is missing, then the piston will move too quickly when the throttle position changes.

http://www.hubbellpowersystems.com/pole-line/deadend/guy-hook/

My guess is that it is from the power company. Perhaps California Electric or California Edison. It appears to be a tensioning cleat or something like that. Or as you proposed, it could be a climbing foot peg.

If you look at the one on the opposite side of the car, I'll bet it is bent and may already be cracked and ready to fail. Total crap design.

Did you overfill the master cylinder fluid reservoir? In preparing my car to run at Sebring the first time, I replaced the brake fluid with Motul 600 and added cooling ducts to the front brakes. Unfortunately, during the brake bleeding I overfilled the rear reservoir. About 15 minutes into the first session, the rear brakes overheated and I was not even driving the car all that hard. Inspecting the car in the paddock after the session, I discovered the overfilled rear reservoir was pressurized. As the brake fluid heated, it tried to expand but because the reservoir was full it had no room to grow. The expansion caused the rear brakes to drag slightly and continuously. Eventually, the rear brakes overheated.

Thanks. Every composite part that I have played with needs work to fit right. I'm used to it and accept it.