74_5.0L_Z

I am starting from scratch from the firewall forward. The front frame and struts were wasted, but the car was perfect from the firewall back. I cut the entire front off at the firewall. I have to reconstruct all the front attach points including the top mounts for the struts. I already have all the lower points established (assuming I get the correct placement of the crossmember holes). SLA? Single Live Axle? Thanks, Dan

Thanks Pete, Jeff, Mike Pete I thought about moving the crossmember forward, but decided against it because I don't want to modify my driveshaft or exhaust. I am moving the T/C mount up 3/4" and out 1/4" to match the JTR mod of the front crossmember. I am also going to a heim joint and clevis rather than the stock T/C box and bushings. I am going to use the Ground Control caster/ camber plates, and I am considering moving the strut upper mount back to gain some caster. Dan

My car is an early 260Z. It had the narrow (240 style) bumpers, and turn signal placement. Further, I always thought the crossmember, T/C rod, and sway bar were interchangable between the 240 ,260, and 280. I believe the 280Z drawing may be correct, and the 260Z drawing has an error. I need to be correct on this because my engine is insalled on plates that are referenced to the crossmember position. If I get it wrong, my engine position will not be the same as it was. I dont want to have to modify my exhaust, driveshaft, and steering link. Thanks, Dan

On May 27 I wrecked my 5.0L 260Z. I demolished the front unibody. The car was completely rust free so I cut the car at the firewall and have started to build a full chassis and cage. I am using all the suspension parts that I already have; therefore I am building the chassis to use the stock suspesion attach points. I have already installed a full frame 2.5" square that extends from the rear subframes all the way forward. I used the frame drawings in the Nissan 260 manual to establish the crossmember attach point. Last night, as a final check before building the front cage section, I dummied up the front suspension to check alignment. The front crossmember appears to be too far back. I have double checked all my measurements against the frame drawings, and they agree. This morning, I checked the 280Z drawing and see that point B is given a dimension of 12.88 as compared to 11.3 on the 260Z drawing (this difference would seem to put the crossmember where it belongs). Pete, I know you built front frame rails. Where did you place the rear bolt of the front crossmember relative to the firewall. On the drawing the firewall has a dimension of 54.5. Can someone pleaes measure from the vertical portion of the firewall to the rear bolt of the front crossmember and give me the value. Thanks to all in advance, Dan

I am using the Dynomax block huggers on my 5.0L 260Z. They work well, but I had to add an extra U-joint and support to get the steering shaft to clear. Mike(scca) did a steering shft mod similar to mine. Don't use the gaskets that come with the headers (they're junk). Buy some copper header gaskets.

I have 10" springs fron and rear. (250lb/in on rear, and 200lb/in front) With 15 x 8 5" wheels BS wheels On the front, I have ~1/8" clearance between tire and spring. On rear, I have ~1/2" clearance. With 16 x 8 5" BS On the front I have ~3/8" clearance, and 5/8" clearance in rear. I don't like the idea of going to an 8" spring because you have to run ~350lb/in to prevent spring stack.

I have two sets of wheels for my car. The first is a set of Centerline Billet Scorpions (15 x 8 with a 5 in backspace). On these, I have Dunlop SP8000 tires 245/50/15 on rear, and 225/50/15 on front. The other wheels are Centerline Billet style 816 (16 x 8 with 5 in backspace). On these are mounted 245/45/16 Kumho Victoracers. These tires all fit within the factory wheelwells on a Z fitted with coil-overs. Centerlines are good because they let you specify the bolt pattern and backspace. They are relatively inexpensive (~$160 /wheel), and are fairly light (~16#/wheel for the 15", ~18#/wheel for the 16"). There are lighter wheels out there but are generally much more expensive.

If you want to build a stroker based on the 302 then the 331 is the way to go. The 331 has a much better rod ratio than the 347, and the wrist pin doesn't interfere with the oil ring. I plan to build a 331 if I ever kill my 5.0 bottom end. My stock 5.0 bottom end has ~200,000 miles on it, and has never been rebuilt. I have a set of Edelbrock performer heads(P/N 6037), cobra intake, Crower 15511 cam, 24# injectors, 73mm MAF, and 70mm TB. The engine has taken me through the 1/4 mile at 112 mph.

Brian, As a fellow autocrosser, and as a owner of a 5.0L powered Z, here is my solution. First, I removed the stock proportioning valve. I simply unbolted the lines from the valve, removed the valve and reconnected the lines with brake line couplers. Second, I installed a Wilwood adjustable proportioning valve in the line going to the rear brakes. This can be placed so that the adjusting knob is in the cockpit, or the engine bay. Third, I drove the car and adjusted the bias to get all four wheels to lock simultaneously. Be sure that the rears do not lock first. The car will instantly swap ends. I have Mike Gibson's stage II breaks on the front(11.75"), and 10.75" vented disks on the back. The front calipers are Outlaw with (4)1.75" pistons, the rear are Outlaw with (4) 1.375" pistons. With this set-up, the proportioning vale is adjusted ~ 75% of its limit to prevent the rear tires from locking first. P.S I outbrake everyone at my local autocross.

I am using the Crower 15511 hydraulic roller cam in my 1989 powered 260Z. The car has the stock 5.0L bottom end, Edelbrock Performer Aluminum Heads 1.72 Roller rocker arms, Cobra intake, 24# injectors, 73mm MAF. The cam has the following specs with 1.6 rocker arms: Part # Description LC Adv Duration Duration @ 050 Gross Lift w/1.6 RPM Range Kit # 15511 Excellent 5 speed cam, shifts @ 5800 114 278 / 282 218 / 224 .468 / .486 1800 to 6500 redline 84562 The lift for 1.72 rockers increases to .503/.525 I am quite happy with this setup. I have run 12.60s at 113 with autocross tires on the car (autocross tires suck at the 1/4 mile). The car pulls very well from just off idle to the rev limiter.

The stock fuel pressure is 39 psi. Measure this by disconnecting the vaccum hose to the regulator. The stock regulator keeps the pressure at 39 psi above manifold pressure. The measured psig (referenced to atmosphere will vary from about 32 psig at idle to 39 psig at WOT. With the stock chip, 19# calibrated MAF, and an adjustable FPR, people have seen improvents by increasing the pressure to about 41 to 43 psi. I have a C&L 73mm mass air and 24# injectors, but haven't changed the FPR. Dan

I am using an MSD P/N 2525 electric fuel pump. Its an inline fuel pump that flows 48 gph at 39 psid. Mount it low in the rear, and run it using the EEC-IV fuel pump relay. I assume you are keeping the fuel injection. This pump can support ~500 HP, is cheap (~$110.00), and is small, light, and relatively quiet.

By the way, if you place your engine as SCCA and I have then the 5.0L FI will clear the factory hood(barely).

I have described the placement of my engine in previous threads in the Ford section. Use the seach function and look for posts by member # 100.

SCCA mandates 0.120 seamless 1.75" diameter(mild steel), or 0.083 alloy steel 2" diameter for the main hoop (2500 lb car). They also "suggest" using the same thickness on all supporting members.

I would be very careful using any process that requires heating an aluminum wheel. You may change the temper or age harden the aluminum. Age hardening occurs in aluminum alloys when heated to over ~200C. Age hardening can make aluminum brittle. There was a case in Gainesville FL where an aluminum scuba tank was anodized. The heating from the anodizing process aged the aluminum and made it brittle. The tank was then taken to be filled. The tank exploded when it was filled killing three people and destroying the scuba shop.

It will take 350-360 rwhp to put a 2500lb (2800 w driver and fuel) Z into the high 11s.

I use my car for autocross, street, and some drag. I am currently using 250# spring in the rear(10 in free length), and 200# springs in the front(10 in free length). I am very happy with this set-up. The car has a 1" sway bar up front, and none in the rear. I disconnected the rear sway bar because I don't have a posi. Here are my suggestions: 1. If you have a posi, use 225# rear springs, and a rear sway bar. Use 200# front springs. 2. If you don't have a posi, then use 250# rear springs, no rear sway bar, and 200# front springs.

As a side note: use the starter fom a 91-93. The later starters are factory high torque mini-starters. The older (pre-90) starter are ~ 10 lbs heavier, and interfere with the block-hugger headers.

Gene is right about the balance differences. The old and new flywheels also have a different number of teeth on the ring gear. I just bought a new 5.0L flywheel (stock replacement). The best deal I found was at Racer Walsh ($98.00).

The 289 can really be made to rev. My best friend and I run a 1964 comet in NHRA super stock. The car weighs 3250 lbs., and has a 289. With stock rotating assembly, stock compression, and stockk Autolite 4100 carb, the car runs 11.18 @118 mph. The class allows any cam (custom .740 lift roller) and valve train (Jesel rockers and stock valves), any intake (victor Jr). The car runs 1.48 60' times with no trans brake, and goes through the traps at 8800 rpms.

The stock spring rates front and rear for the 240Z was 90 lb/in. I am autocrossing my 260 and am using 250 lb/in in the rear, and 200 lb/in on the front. This is too stiff for the street. For the street try 150 lb/in in front, and 175 lb/ in in the rear.

They usually have 2-3 day turn around from the time you order till the time the stuff gets to your door.

I use AFCO racing for all that kind of stuff(rod ends(heim joints), threaded tubing, AN fittings, etc... They have an excellent on-line catalog at www.afcoracing.com

Tom, Pardon my silly question, but have you measured the temperature with a calibrated gage. Before I switched from the stock Z gages to the autometer mechanical gages, my temperature looked high and my oil pressure low. After going to the mechanical gages, I can now put actual values to pressure and temperature. The car run between 180 and 190 all the time (185 degree thermostat), has 70 psi of oil pressure (warm on the highway). Before my stock water temp gage indicated about 3/4 scale. Good Luck, Dan