COAL Update: 1974 Pontiac Firebird Esprit — In Praise Of Fun


I could easily have titled this piece “In Praise of Folly,” after the titular character in Erasmus’ classic manifesto, “for I well know how disingenuously Folly is decried, even by those who are themselves the greatest fools.” Unfortunately, in case you were wondering, Erasmus has nothing to do with cars, but that doesn’t make him wrong.  Most of my purchases have a sprinkling of folly involved; for example, I accidentally thought the other day about how much money I must have sunk into my worthless Corvair, and immediately ceased pursuing that train of thought in order to stave off some day-sadness.  On the other hand, the Firebird’s ledger reads a comparatively reasonable six-thousand dollars, which is actually in the neighborhood of what it’s worth.  That is a refreshing change of pace, although it’s silly to think it permanent.


Although I would almost always lose money on my vehicular flights of fancy, if I ever sold anything, I suppose it could be worse.  I could be a perfectionist.  I’ve always felt a little sorry for perfectionists, because my latent level of anxiety is usually inching toward “Code Red,” even though I tend to let a lot of things slide.  Therefore, it’s only fitting that I have a spectacular collection of what some call “twenty-footers,” meaning they look great from twenty feet, but have a few issues upon close inspection, some more than others. That’s fine with me, however, because I like driving my junk and, in the words of some budding random internet Socrates, “If you’re not having fun, you’re doing it wrong.”  Well said, my friend. After all, a bad day in the garage is, well, you know the rest.


For those of you who have been following my not-that-interesting life, you may recall that I picked up the Firebird on eBay back in December, and it had been sitting for around 15 years.  To get it on the road, I had to replace every single piece in the brake hydraulic system, and many of them had 42 years of rust buried deep in every thread, nook, and cranny.  I’ve replaced the pads and shoes and u-joints, too, along with all belts and hoses and the fuel pump.  More on that in a bit.


The interior was fetid and repulsive, so my mom spent a day deep cleaning years of yuckiness, and my wife bought a pair of original red “GM” floor mats.  After a new set of tires, I was on the road.  In fact, I’ve already driven the Firebird over 600 miles, which isn’t bad when considering my “beyond all rational reason” fleet of cars.


Those 600 miles have not, however, been without issue, as one might expect from a car that’s been sitting forever, although some problems were caused by newer parts.  My new fuel pump sprinkled a trifling three pounds per square inch of fuel pressure to a carburetor expecting six, and the carbon canister was clogged, and both conspired to leave the Firebird chugging and gasping on the highway and under heavy throttle.

If it weren’t for my removing the fuel cap to test for tank venting, I may never have figured out the canister problem, and teeing in a fuel pressure gauge and taping it to the windshield told the whole story of a dropping pressure gauge under load.  Therefore, I’m now on fuel pump number three, and I rebuilt the Rochester 2-barrel for good measure.  The float bowl was filled with toxic sludge, so I dropped the tank to check the sock and general condition, and it was clean.


Funny thing: fuel pumps for non-air conditioned 1974 Pontiac 350s have been discontinued.  I’m able to use the AC pump by blocking the return port, which sounds scary, but it’s been working out so far.


The interior hides an abnormality: the driver’s side kick panel is for an air conditioned car and the passenger one is not, and my car is not air conditioned.  Bright red kick panels aren’t exactly available at the local NAPA, so this car was assembled by a confused line worker on a Monday morning or someone along the way didn’t like kick panel vents.  The interior otherwise looks original.  If anybody is sitting on a bright red non-air kick panel, please let me know.


All was not sunshine and rainbows on the exterior either.  The rear bumper took a hit (as did the left quarter) at one time, and someone had spilled a caustic chemical onto the trunk lid and hood, lifting the paint.  Therefore, I’ve done and had done a bit of paintwork, so all the paint on the car is Buccaneer Red, give or take a half-shade, which bugs me a little but not as much as painting the whole car. After all, I think my three hours wheeling out the paint worked wonders.  Once again, from twenty feet (I exaggerate.  It’s a five-footer.), it looks amazing.


Here’s what it looked like on the day I brought it home.

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This is the peeling spoiler and trunklid.


This is after a bit of paintwork.


And here it is now, but I digress.

Unfortunately, 1974 models have a mess of rudimentary emissions equipment, including an EGR valve and a variety of vacuum and temperature switches to operate the vacuum advance when Mercury is in retrograde or a Strawberry Moon appears.  I disabled all of that (Emissions testing in Michigan?  Draconian!), but that leaves me using manifold vacuum advance rather than ported (there is no port for it).  Some of my cars like that, but this one doesn’t, so I’m still juggling timing curves and vacuum advance diaphragms and rates to find the best combo.


On a related note, the previous owner installed an HEI distributor, which is fine.  What isn’t fine is how he simply plugged in the resistor wire, leaving it to run on eight or nine volts to the coil, which does not make an HEI very happy. I resolved that situation by attaching a relay where an old emissions relay once hung out on the firewall, and by doing so, I get full battery power to the HEI at all times.  Before you say anything: I don’t care if you think soldering connections is better and I know the wire that activates the relay is janky right now; it’s the resistor wire that was heretofore plugged into the distributor itself, so I’m not responsible for its appearance.


Here is my makeshift electrical hack schematic.  I ended up running the hot wire straight from the battery, because the starter looks like it hasn’t been disturbed in quite some time, and I wasn’t in the mood for breaking any bolts or studs that day.


I’ve also spent some time with my rigged up wideband O2 sensor setup, getting to know that vagaries of emissions-era Rochester 2GC carburetors.  It turns out that they’re exceptionally lean on the idle circuit, to…pass emissions.  Said leanness also creates a light throttle miss, at least on my car.  After hooking it up to the scope and finding no electrical faults, I removed the carburetor lid and venturi cluster, got out the pin drills, and started modifying the idle and transition circuits.  Don’t try this at home unless you’re brave, stupid, or used to messing with old carburetors.  I’m all three.


The 2GC is actually a very simple design, and most circuits are contained in the venturi cluster, shown above.  I drilled the small tubes .005 inches larger, and the idle restrictors (hidden in the outer holes) .008 inches larger. This is all actually a big swing, but it now runs better, if not perfect.  I did not have to rejet the main circuit, as the car cruises on the freeway at an AFR of 15:1, which is about perfect for many stock engines.  At light throttle when I began, AFRs were approaching 16.5:1 at lower speeds, which is a pretty lean mix on today’s gasoline.  I’ll trade a little fuel mileage for driveability.  AFRs at slow cruise are now in the mid-14s to 15:1.


Enough pseudoscientific gobbledygook, let’s return to the basics.  In my first article about the Firebird, I mentioned that I like the ’74 as much as I like the ’73.  I’m not, however, sure that I like the extra front overhang that is only really visible from the side.


That’s really where the ’73 has it all over the ’74; well, that and the Super Duty 455 in this particular ’73, but the money tree doesn’t grow in my backyard.  Come to think of it, I don’t have a tree in my backyard.


On the other hand, some like the 1975 model’s curved rear window, while I think the flat glass and its triangular pillar are one of the best parts of the whole car.  I could look at this for hours.


Additionally, unlike some of my other old cars, like the Dart and the ’53 Special, the Firebird is right at home on the freeways of America, cruising effortlessly at any prudent speed, with less wind noise and a better ride than I’m used to from my ’50s and ’60s cars.


So there’s my update.  If I’m lucky (I’m not always), I won’t have to write much about the Firebird in the future, because I like its level of nice-looking rough around the edginess.  It’ll certainly break and otherwise give me fits, but they all do that.

And speaking of fun and folly, it’s now time to pull the Dart out of the storage barn, where it’s been for months, and do something about that noisy differential.

Further Firebird Reading:

Decoding a Firebird and a Dart

Headliner Repair