NEW  Relocating the front seat for more legroom    
NEW  Fixing a dim dashboard      
NEW  Auto-dimming mirror     
 
Suspension rubber...and seven shocks
Fuel lines, filters, insulation
Eliminating the 1966 carburetor
Fixing vacumm headlights that won't go/stay up or down
Internally-regulated alternator ('66-forward with OE-type external voltage regulator)
Electronic switch-pitch controller ('66 and '67, plus any later years that have a 66-7 transmission installed)
Electronic ignition (all points-type, non-HEI Toronados)
Electronic turn-signal flasher
Horn relay
Flarestat hazard lights into a 1966
Cooling system (4-row radiator, HD fan clutch, radiator and heater hoses, thermostat, heater control valve, and heater core)
Radiator overflow tank
Center-mounted 3rd brake light
VIN glass etching
1966-67 headrests
Putting a collapsible steering column into a 1966
Modern 3-point seat belts      
     

Relocating the front seat for more legroom
If you pull back the carpet from your seat mounts, you'll discover that the seat brackets have a second set of holes. Undo the nuts on the mounting studs, lift up the seat, and you can move it back for an additional inch of  legroom.

Fixing a dim dashboard
To fix dim dashboard lights, you'll have to drop the dashboard. Follow the shop manual procedure carefully, and don't break the transmission indicator needle!  The most obvious step is to replace all the dashboard miniature lightbulbs, but there are some tricks that will make it a thorough job.  Be sure to buy high-quality heavy-duty or long-life bulbs--you don't want to do this again anytime soon.  The shop manual lists all the bulb types and quantities needed.
--First, with some fine sandpaper, sand VERY lightly the contacts on the plastic sockets, as well as the areas on the copper printed circuits that the sockets screw into.  Don't sand away the circuit, just remove the thin layer of oxidation so you get better connections.  
--Second, when installing the new bulbs in the sockets, use a knife edge or small screwdriver to bend the bulb wires outward very slightly to ensure tight connections.
--Third, when reinstalling the sockets, bend the metal contacts outward very slightly to ensure tight connections to the printed circuit.
--Fourth, lightly sand any wiring harness connectors on the dash to remove oxidation/corrosion. On those plugs, you can apply a very light layer of dielectric grease (used on spark plugs) on the contacts to prevent corrosion.  
--Fifth, in the headlight switch to improve the circuit  you can lightly sand off corrosion on the contacts that press against the coil rheostat (which adjusts the brightness of the dashboard lights.  
--Sixth, there are several bulbs that fit into metal sockets that have small holes for light to escape. In early years, these include the AC fan control, the cruise control dial, and the ignition key. On a '70, the labels for the headlights, wipers, ashtray and lighter are illuminated this way.  If you remove these metal sockets, you can use a small file or screwdriver to slightly enlarge the holes and let more light out.

Auto-dimming mirror
One nice thing about new cars is the auto-dimming mirror which turns dim green when someone comes up behind you. I haven't tried it on my '66 yet because of the chrome bracket, but put one in my '70 a year or so ago.  Any car that has a glue-on rear-view mirror mount can be upgraded to a auto-dimming Gentex (it's their patent) mirror. You can buy one new, or there are a bunch for sale on Ebay.  Look for one off a late-model GM car (the newer ones work better and are less bulky), and  make sure it comes with the harness. You'll need to buy a new mirror mounting kit consisting of the mount and cement at a car parts place for a couple of dollars.  You can get one with dual map lights (nice, since the Toronado has no overhead lights), and even with temperature and compass if you want.  Depending on the number of features, the price may range from $45-100.  Give yourself maybe an hour and a half for a first-time installation.  Hiding the wires under the trim on their way to the fusebox is probably the slowest step.

Suspension rubber...and seven shocks

Okay, your Toronado is never going to go through corners quite like a new Corvette, but you can  make it much more predictable at speed and flatter in the corners than it is now. No more wallowing, rolling, and swaying, just a really big car that handles with surprising ability and grace.

KYB gas shocks are still available for the front of early Toronados. Part number KG4501, available from www.shockwarehouse.com and others, around $30-35 each. These are by far the best shocks I've found for these nose-heavy cars: not harsh, but very firm, and with a very long life. They will make a dramatic difference in how your car handles. I've tried other front shocks, including some gas ones, but they were either mushy or harsh, and didn't last long. When replacing the shocks, you'll want the car up on a lift or jack stands. Keep a floor lift handy--you may need to jack up the A-arm a half-inch or so to align the top mounting bolt.

While you're at it, consider replacing the endlinks and frame bushings for the sway bar. Rubber or urethane, either will make a noticeable improvement. Even if your car is low mileage, the rubber will have hardened with age. Plus, I've seen a number of original end-link bolts that were rusting to pieces inside the metal spacer tube. If the replacement bolts are too long, just saw off the excess after installing them.

There also are rubber bushings in the control arms and the rear spring eyes and shackles, but those are bigger undertakings. The shocks and swaybar rubber are probably the best thing to start off with.

There also are rubber body mounts between the body and frame, but I haven't heard of anyone trying to replace them.

Rear shocks also are easy to replace. I got my last pair (gas) from Carquest, so they're not hard to find. The vertical pair, at least. Reasonably priced, too. However, the short horizontal pair seems to be available only in generic form from places like USA Parts Supply and Kanter. The horizontal ones don't seem to make as big a difference in handling, though, as the vertical ones. I think they were included to help reduce axle hop during hard braking.

Finally, there's the shock that is mounted sideways to serve as a damper in the steering linkage. It connects the steering center link and the frame. This, too, it seems is available only from specialty firms. It will, however, make the car's steering a bit more stable and resistant to bumps.  It was eliminated from Toronados by 1970.
 

Fuel lines, filters, insulation
The ancient fuel hoses coming out of the tank and up to the fuel pump can and should be replaced. The biggest trouble spot seems to be the sharp bends as they connect to the pump.  But, remember that there also are hoses at the back of the car coming off the top of the tank and through the frame to the metal lines on the side frame rail. Do NOT use old-fashioned R7 hose, which is usually the cheapo stuff on the big rolls at the parts stores.  Insist on modern R9 hose, which is intended for high-pressure fuel injection systems. It’s more expensive than basic fuel hose, costing maybe a dollar a foot, but much more durable and resistant to heat and curves. Any spring-type hose clamps should be replaced with ones that can be tightened.

Sometimes the metal line from the fuel pump to the carb has been replaced with a rubber hose. This substantial fire hazard can be eliminated with a pre-formed metal line from Inline Tube.  If you need a temporary fix, use a piece of R9 fuel hose with hose clamps.

The carburetor has a tiny filter and servicing it brings the risk of stripping the carb’s fuel inlet threads.  Carefully replacing it once and then adding a big inline filter before the fuel pump is good insurance, especially with the rust and junk that may be in the bottom of the gas tank.  Fram filter # G15 works well for the inline one.

JC Whitney and others sell inexpensive kits with fiberglass insulation sleeves that slide over the pump-to-carb metal line and make it unlikely that fuel in the line will boil and cause vapor-lock. If your cooling system is in good shape, that shouldn't happen anyway.

Eliminating the 1966 Carburetor
Most if not all 1966 GM Quadrajets have a dangerous design flaw--they use a rubber plunger instead of a brass needle-and-seat valve. The rubber can degrade and fuel will flow uncontrolled into the carburetor. Any carburetor with this design should be replaced with a later version.
 

Fixing vacuum headlights that won't go/stay up or down
Headlight cannisters: Most headlight problems on '66 Toronados are in the headlight cannisters. The pic shows what was inside one of my cans.  These often fail because of internal corrosion, poor sealing, frozen release actuators, or broken return springs  (1967 ones have problems, too, but their design is different and they are NOT interchangeable with the '66 ones). RT Engineering sells everything you need to repair your cannisters--new springs, stainless steel piston rods, and a spring-loaded sealing kit to prevent any internal vacuum leaks. I think the full set of parts for two cannisters was something like $50 or so. Be aware that the mounts for the cannister, especially the lower one under the fender, may be corroded/frozen. If you break the little swivel-ball there, you can build a substitute using a small stainless steel eyebolt from the hardware store.  Be careful with the nuts on the shaft--if you break the shaft you're in trouble...

Headlight switch:  This is easiest to remove by disconnecting the dashboard. Remove the set screw on the knob, then unscrew the bezel. The switch then removes from the back of the dashboard. If you CAREFULLY disassemble the switch, you can clean the rubber slide that controls the vacuum to the headlight cannisters and lube it very lightly with lithium  grease.  Be sure to restore the slight arc to the piece of spring steel that presses the rubber to the metal plate. You can also lightly sand the metal contacts inside the headlight switch. Be careful with disassembly and assembly--you don't want to break anything on these hard-to-find switches. When re-installing. trim a quarter-inch off the vacuum lines to ensure a tight seal.

1967, '68, and '69 Toronados use parts in their systems, but the principles are the same--eliminate binding and vacuum leaks.

Internally-regulated alternator ('66-forward with OE-type external voltage regulator)
With the Toronado’s external voltage regulator, headlights and turnsignals will dim and slow down at idle. An internally-regulated alternator will bolt right in and fix these in 10 minutes. The old regulator can be removed. The only complication is possibly having to remove the 4 bolts on the back of the new alternator and rotate the back half of the case to get the terminals in the correct position (viewed from the front with the mounting brackets in the right clock positions, the harness plug should be in the same position as on the original alternator).  If this is done, a temporary wire in the little hole near the center of the rear will hold the brushes in position. If they fall out, the case can be pulled apart to re-install them.

AC Delco part number 321-39 works well. It’s an alternator with internal voltage regulator,  Model 10Si, for a 1979 Oldsmobile with a 403 engine. It’s 63 amps, which is more than the original one.  It should cost about $60. Off-brands obviously will be less.  You can also use a 12Si, which is 80 or so amps, but it’s more expensive. Some of the higher-amperage ones for later years have a plastic cooling fan that doesn’t blend well visually with an old car, if the old-style metal fan is important to you.

The other necessary part is a Year One wiring harness HU-30, which contains a 5-inch adapter jumper wire for the harness-alternator connection and a plug to go over the connector that presently goes into the external voltage regulator on the driver’s side firewall.  It costs about $15. They also want another $10 for shipping, and they win a Golden Cocoon award for completely pointless packaging by delivering this tiny kit in a shoebox sized package instead of putting it in a small padded envelope with $1 postage. But, the harness works and is nicely made.

Electronic switch-pitch controller ('66 and '67, plus any later years that have a 66-7 transmission installed)
1966 and ’67 Toronado transmissions have switch-pitch torque convertors. Bruce Roe sells an electronic controller that will dramatically improve acceleration and smoothness.  I am thoroughly impressed by its quality and its impact on performance. It is well-engineered and has great instructions. Installation isn’t difficult and takes 2-3 hours for the patient first-timer.   Be sure to seal the end of the unused transmission wire so it doesn’t short out. I didn't, and it took me awhile to figure out why the controller blew the under-dash fuse.

Electronic ignition (all points-type, non-HEI Toronados)
Some people don't mind points, but I'm lazy. Replacing the old-fashioned ignition points with an electronic ignition means the engine timing won’t need regular adjustment.   Pertronix (www.pertronix.com) makes a nifty conversion that fits inside the existing distributor cap, as well as an matching upgraded coil to go with it.  Installation for the first-timer takes an hour and a half. The ignition module costs about $65 and the coil about $25.  There are other suppliers as well, and you can always replace your system with a GM HEI from a later-year car.

Electronic turn-signal flasher
The old-style thermo-mechanical flasher is slow, and gets realllllly slow if the headlights or fan are on.  It can be replaced with a nice modern electronic one by removing the painted metal panel (4 screws) underneath the dash on the left side of the steering column to expose the old flasher.  If the car has hazard lights, that flasher can also be replaced at the same time. Parts stores have two kinds of flashers—regular and electronic (the improved one).  This is a 5-minute job. The flasher costs $8-10. While you're at it, you can replace the hazard light flasher with an electronic one, too.

Horn relay
Wow. I thought my Toros had worn horns or something since they sounded weak.  Turns out that the problem is usually that the relay has degraded with age. The horn relay is on the inner wheelwell on the passenger side. Replacing it is cheap and easy, and makes a huge difference.  Now the cars sound like they did when they were new--rich and loud.  If you have a '70 or later Toro with the key warning buzzer built into the relay and can't stand it, just disconnect the wire (pink on a '70) and that awful sound goes away for good.

Flarestat hazard lights into a 1966
Having a car with no hazard flashers is pretty scary when you break down on a busy road. These optional hazard flashers aren't easy to find, but they're a breeze to install. The harness plugs into the steering column harness and a hot wire goes to the fuse box. There are even some mounting bosses on the back of the lower left trim panel under the dash. Take off the trim panel, drill out the bottom of two bosses, and you're ready to screw the unit on. Before installing it, it's a good idea to take apart the box and clean any corroded or oxidized contacts--which they are very likely to be after 35 years. Market price for the units seems to run $35-50.

Cooling system (4-row radiator, heavy-duty fan clutch, hoses, thermostat, heater control valve, and heater core)
That big engine puts out a lot of heat. A bigger radiator, an up-graded thermostatic clutch for the cooling fan, new radiator and heater hoses and a good 185 degree thermostat eliminate any cooling worries.  The radiator work (either ordering one or having a 4-row core installed at a local shop) may cost $150-250. One thing to be very picky about--make sure the tank on the new one has the right size fittings for the transmission cooler lines. If they try to give you one that has smaller fittings, that means the cooling capacity of the transmission fluid cooler is lower and won't cool your car as well. Don't let them try to give you adapters to reduce the ends of the Toronado lines--this doesn't fix the problem, it just lets you install the inadequate cooler on your car. A 4-row core is about half an inch thicker than a 3-row, so you may need to get a shorter fan clutch or the fan will hit the radiator.

I find that a fair number of people forget to replace the heater hoses and thermostat when they do the radiator hoses.

If the heater core fails, you'll start smelling antifreeze inside the car. Unfortunately, that's a real pain to replace.

However, you can easily prevent another source of overheating by replacing  the heater control valve on the back of the intake manifold. It has a rubber diaphragm in it which is almost guaranteed to fail at some point.  Replacement versions may need an reducing adapter to securely attach the original vacuum line.

Radiator overflow tank
Adding an overflow tank reduces coolant loss and pollutes less. Cost is about $10.   I like to use Sierra or one of the other low-toxicity antifreezes. Animals like the taste of traditional antifreeze, but it will kill them.

Center-mounted 3rd brakelight
The brakelights in the 66-67 cars aren't bad, assuming you can get all the bulbs to work consistently. The biggest problem is usually the sockets. It is easy to replace them with new, high-quality light sockets. The brakelights in my 70 are lousy--buried in the bumper and hard to see.  For any old car, though, adding a 3rd brakelight in the rear window only costs $10-25. Toronados need one with a logic circuit so that the light won’t blink with the turn-signals.

VIN glass etching
To help discourage a professional car thief, the car’s serial number can be etched in the windowglass using a inexpensive chemical kit from www.autoetch.com or with an engraving bit in a Dremel moto-tool.

1966-67 headrests
Headrests are very easy to add to early Toronados. They look cool, may save your neck, the holes are already there for the brackets, and the only thing you'll have to do to your seats is poke a couple of holes in the top of them and trim some excess upholstery to mount the brackets. GM used the same headrests for all their cars with bucket-back seats, so something listed for 66-67 Chevelles, GTOs, whatever, will fit. They show up on Ebay occasionally, but are now also available as reproductions (in black only, but you can dye them).  The repro hardware is also available. Total cost $250. I think it was either the Paddock or Year One that listed them.   Headrests for bench seats are now available in reproduction and are extremely scarce. More good news is that if the molded vinyl is cracked or the wrong color, a good upholstery shop can re-cover headrests with stitched covers, or you can go the very expensive route through a couple of specialty firms of having the molded vinyl replaced to look perfectly original.  Me, I'd just get the upholstery shop to do them. 

Putting a collapsible steering column into a 1966
1966 is the last year of the solid-shaft non-collapsible Impale-o-matic steering column. Starting in 1967, GM's columns have a collapsible middle section. If you want proof the collapsible design actually works, go here:  www.angelfire.com/ca/mineryhomepage/67accident.html  It's easy to remove the column from a 67 or 68, and then you can change over the stalks and steering wheel. You could also use a 69 or 70 column, but those have the ignition key in the steering column, not on the dash, so things will look a bit odd. You can also use your '66 turnsignal switch and wiring. However, since the 66 turn signal switch is scarce and expensive (especially the tilt/tele one), you can also use the later switch and wiring with minor work on the wiring connector. Another nice thing is that the later column has a built-in hazard light switch.

Modern 3-point seat belts
No one wants an accident--that's why they're called accidents. But, you can save your face and torso from smashing into the steering wheel, and spread the deceleration load across more of your body, by using a lap/shoulder belt combination. 1966 Toros have no shoulder belts, but 67-forward have shoulder belt mounts for the front seat already under the headliner (fairly far back on the roofline). For the first couple of years, the shoulder belts were optional, so you may not see the mounts, but you can feel them under the fabric. It's also possible that some 66s have the mounts. The separate shoulder belts are very inconvenient to use and are anchored so high that they cut into your neck. You can easily retrofit modern, comfortable, convenient, 3-point retractable belts into your car, and they are available in a variety of colors. One supplier is www.andoauto.com   If you do this, I suggest you get a version with a longer shoulder belt anchor to lower the belt and get it away from your neck. A pair will run you about $150. That's MUCH cheaper than facial reconstruction or a funeral, and hurts less, too. You can also retrofit shoulder belts into the rear seat.