DaveN

70 an 71 seat belts were identical. It you find a set with the detachable shoulder belt mentioned above they're correct. Be wary of the webbing and stitching after 37 years. Faded or frayed nylon is a sure sign they've been weakened by exposure and use.

Agreed, sounds like it's just idling too low. If that isn't it another possibility is an idle mixture just a little too lean, either due to adjustment or to a small vacuum leak.

Yeah, been there. Devils hide in the details, sometimes in plain sight. Maybe these ideas will restart the thought process-- Have you double checked all the vacuum hoses and manifold connection points? How about hidden vacuum leak points such as a failed vac. advance diaphram. Are the PCV hose connections tight at both ends? Is the EGR system hooked up correctly (or are the manifold ports sealed)? Have you checked the "choke" adjustment -- at least 6-7 mm additional nozzle drop at full choke? Is the gas fresh? The high vapor pressure fraction you need for cold starts evaporates easily. Were the 72 carbs clean when they went on? Some gas can gel during storage, and a tiny lump in the nozzle will block flow.

My first 72 had the same configuration, a 6->2 header, then dual pipes (over/under at the tips) with 36" long small diameter glasspacks tucked into the tunnel beside the driveshaft. Best sounding Z exhaust system I've ever heard, by far. As smooth as the best sounding Jags. Mine were made by Cannon and discontinued in the mid 70's. The BRE system looked identical and disappeared from their catalog at about the same time.

Tim, Just a few thoughts: 1. Rust gets worse over time, so needs high priority. Also obviously needs to be fixed before you paint. 2. You'll get a neater appearance putting new weatherstripping on after painting thay by trying to mask around it. 3. Running rich is usually caused by things you can fix with a DIY rebuild. It's definitely worth a try. If you're new to SU's we can get together, I'm in Hickory and have been tuning & maintaining my own roundtops since '71. The first thing to do is find out exactly which version you have. There's a good description on the ztherapy web site. 4. Adding A/C to an early Z causes severe overheating problems in traffic. Search forums here & on other sites. You'll find many examples of the problem and solutions. All are more or less expensive and some sure to raise under hood temperatures, which you don't want to do in an early Z with the high vapor pressure of modern gas. 5. Your old A/C is an R-12 system. R-12 is very expensive & hard to get these days because it's an ozone destroyer, it's been replaced by R-134a. Parts for R-12 systems are getting even harder to find than R-12. If a conversion kit available a pro may be able switch it to 134a. Make sure you can (and want to) restore it as is or do the conversion before spending any more money on it. 6. Seats probably need new foam after 34 years. Mine do, badly, on a car that's been kept in a garage most of its life.

That temp gauge is definitely too high. Assuming its not just a bad gauge or temperature sending unit, have you cleaned all the dirt and bug carcasses out of the air side of the radiator core? ....checked the water pump & belt? checked the temperature sensitive clutch in the fan? ....checked for a collapsing lower radiator hose? Does the car have A/C installed? The condenser in early Z A/C units cut fresh air flow enough to cause overheating problems at low (or no) speed. Part of the problem was hot air recirculation -- air took a short, low resistance flow path from the back of the radiator, underneath it, and up the front to be pulled through again. A sealing panel from the front valance to the bottom of the radiator crossmember blocks that path. You can also fab a foam or rubber lip seal for the gap between the crossmember and the hood. BRE style "chin spooks" may still make thhe lower seal. The one I bought in '71 did, and it really helped (in Albuquerque). A fan shroud also helps in stop and go driving, but causes a flow restriction itself at highways speeds. I needed all three in ABQ summers, but was able to ditch all but the chin spook when I moved to Raleigh, NC. Other owners got good cooling with the lower valance seal and one or two thermostat controlled electric fans replacing the stock fan. Re the thermostat -- get the largest, best streamlined water passage you can find, and run a 180 or 192 opening temperature. Either in good condition will be fully open 20-25 degrees above its rated temperature, and from there to the boil over point the opening temperature makes no difference. A 192 minimizes thermal expansion stresses on the head and gasket by keeping the coolant operating in a narrower temperature range, but could make hot weather stalling (gas boiling in the SU's) worse. Are you running stock SU's? If so avoid a 160 thermostat or change the carb jetting to compensate. A lower coolant temperature leans the mixture a little, especially in the front carb, and the stock 73 (and 72 round top) needles are already so lean that additional leaning is likely to burn exhaust valves.

If you eliminate ALL the gas tank vent hoses you'll have problems, they do more than just keep the car legal in California. The filler cap makes an air tight seal when in good condition, so you need a small vent for pressure relief and to be a vacuum breaker. For safety that line needs to contain (or be small enough to be) a flame arrestor. The little vent hose from the vapor/liquid separator tank to the engine in the quarter panel does that job, and the separator needs a low point liquid drain back to the gas tank. Finally, early Z gas tanks need one fairly large high point vent to fill completely because the filler neck enters well down on the side.

All the early Z's were designed to run on 87 (MON+RON)/2 gas, but sometimes needed a bit more octane after carbon built up in the combustion chambers. Do 77 Z engine controls include a knock sensor (retards timing if a mike hears pinging)? If so that circuit would make the engine hesitate and feel rough when it's knocking. If not knocking mild enough to leave the car driveable wouldn't make it hesitate or be rough during accelleration. Those symptoms sound like an engine controls problem, a wiring fault or a sensor or control unit going bad. If that's the trouble it might be causing the knock, too. You've already checked mechanical alignment during reassembly. Enough about that. My only other thought is that an edge of the (wrong) head gasket projecting into the combustion chambers would become a hot spot and cause knocking. Did anyone make sure the gasket openings really match the head?

Trip mileage (NM - NC before 55 mph speed limit) in 70s on box stock 71 4sp -- 25. Same car, same & similar trips after tweaks -- 29-30. Tweaks were: 1) added A/C, BRE chin spoiler, fan shroud.; 2) vac. advance rebuilt to start a 5 in. vacuum instead of 10 & timing set at 11 degrees initial advance instead of 5; 3) Mulholland 2.5 in. exhaust w. stock manifold, mainifold air injector tubes cut back to 1/4 in. projection into ports. Saw chin spoiler/fan shroud & exhaust mods add 1 mpg each when installed. Day trip mileage in NC in a '72 w. 4 sp & same tweaks (but w/o fan shroud, with 71 spec N-27 needles in SU's), in mid 70's and 80's was about 1 mpg better. In town mileage was sensitive to conditions, 18-20 in Blue Ridge foothills (small town, short trips) to 24-25 commuting in suburban Houston. Knew an owner who got 28 in the 70's on day trips in his slightly tweaked 4 sp 72, 32 after putting in a 5 sp & keeping the stock 3.36 read end. Have another tweaked 72 now, but don't drive it as much & haven't checked mileage. Spark advance tweaks still work w. 93 octane gas (mileage improvement more than offsets higher price), and plugs, valves, and SU's stay cleaner with the lead gone & better detergents.

Back then the original bumpers had fog/driving light mounting holes on the under side some 3-4 inches inside each overrider. That was the usual mounting point. Lights there looked good, but functionality was compromised. Driving lights work best mounted high to minimize shadows where there are dips in the road. Pro rally cars have their driving lights above the bumper or on the roof. But... the pros use ther driving lights to supplement 1 or 2 pairs of Euro style hi/low beam headlights like those on p. 61 of the Black Dragon catalog. The high beams are broad enough to light the shoulders and sweeping bends is enough out to about 1/2 mile, and the low beams are also much brighter, more uniform, and better controlled than sealed beams. Driving lights extend the visibility range to 1 mile plus, but only straight ahead and for 3-4 degrees on either side (the greater the range, the narrower the beam). Fog lights need to be as far as possible from the drivers eyeball level to minimize the amount of light reflected back into the driver's eyes. Under the bumper is better than headlight level, down at the chin spoiler is better still. In really thick fog they also have to be used instead of the headlights (which are too near eye level in a Z). That's illegal in the US, but in a pea soup fog it's the only way that works -- the laws of physics trump the laws of Congress. If you don't already have them either Cibie or Hella replacement headlights will give the most useable improvement over sealed beams. Both companies also make good driving and fog lights. I can't say if either is better today. (Cibie was a bit better in the 70's, and my 72 Z is still running 75 vintage Cibie Z-beams.) Either way use clear (white) bulbs. Your eyes see yellow and green best, and "bonehead blue" bulbs absorb some of the yellow. A heavy duty wiring harness is a good idea with the standard 55/60w bulb -- headlight fuses blow occasionally without it and the voltage drop through stock wiring steals more light than you might think. Heavy duty wiring is essential if the original wiring has deteriorated or if you want to upgrade to 80/100w (illegal on the street) H4 bulbs.

The side winwows are in a low pressure area -- even lower than the back of the car, so you will get exhaust odor pulled back into the car with a window down if there is ANY opening from the area of the car's wake to the interior. You can keep the windows up (or just cracked with the dash vents open /and or the heater fan on high), or become a fanatic about finding and sealing every crack, hole, etc. in the back 2-3 feet of the car, including underneath and in the spare tire well. Making sure the hatch and taillight gaskets seal is just a good start. There are also several gas tank vent hose and wiring harness penetrations, some in hard to see spots, that were not completely sealed at the factory, and you may find some small unused screw or bolt holes, or a bad/missing rubber hole plug. Good luck.

There's next to no clearance between the 72 heat shield and that heated air pickup pipe, so if you can see or measure a difference in the 260 heat shield it won't fit. I would expect a difference, I almost remember seeing a redesigned exhaust manifold on 260's (havent worked on one since the 70's), so would expect the air pickup pipe to bolt on in a different location. Make sure the spring attachment on the heat shield (or whatever) is sturdy and secure. If the spring comes off with the engine running air flow and vibration will tend to OPEN the throttle. Been there, done that.

Hi, y'all, I'm on my 4th 70-72 Z at present, a near stock '72 in "very good" (i. e. high #3) original condition, with 83k miles. I started with a '71 in 1/71, upgraded to a '72 in the mid '70's, wore that one out and sold it back to the original owner for restoration in the mid '80's, then bought my 2nd and current 72 in the late 80's. What was #3? It was s/n 00013, rescued from a Garner, NC salvage yard in the mid 70's, put back in running condition, and sold to a collector after 2 years. Good early Z's (and parts) have gotten hard to find, but they're still worth the search.

Welcome! Sound bodies and frames are rare now and costly, but the added cost of restoring a rusted or damaged car is more than the initial savings. There's a well done tutorial on rust prone areas in another club's (I don't remember which) tech section, well worth finding and reading. Also check carefully for signs of serious body damage, especially upper and lower front frame rail misalignment. Camber and caster are not adjustable, if the frame rails aren't aligned the front wheel alignment will be off, too. The fit of the front sheet metal is unusually sensitive to frame rail alignment in the early Z's, making frame alignment problems fairly easy to spot. The clearance between the air filter and inner fender well is barely enough for access to the filter when all is well, so making sure you can get the outer cover off with everything else in place is an easy way to detect the most common misalignment of the hidden upper left frame rail. Are looking for a Z that is stock or restorable, or planning to customize the car. Cost is no object collectors go for very low s/n restorable '70's, but in stock form the 72's were the best of the 240's for street use. (I have had a 70, a 71, and am now driving my 2nd 72.) Several early design weaknesses were corrected for the '72 model run. New emission controls in '73 hurt performance and driveability badly, but the bodies are OK so if you don't mind major engine mods (get rid of the flat top SU's and EGR) 73's are a good starting point. 260's had a stroked 73 engine engine with tweaks to minimize driveability issues, but the weight of impact rated bumpers offset much of the higher engine power and made handling feel heavier. The "74 1/2 260" was a 260 engine is an even heavier 280 body, a crisis response when the 280 F.I. engine didn't get EPA emission certification in time. If you're willing to consider a 280 check this & other forums for posts re which is the best. In the late '70's we liked the 77's with round exhaust ports, but I don't know whether that has stood the test of time.

According to my parts book (the last paper issue) plastic tanks were used through 6/71, metal started in 7/71.