What was the L-88 Corvette like? – D. Steidinger

I’ve always loved Corvettes.

I thought I’d done really well buying a ‘67 427-435 in ’73, which I loved and kept for almost 28 years. And in many ways that will be another story for you.

And I bought a literal basket case ’59 Corvette in ’76. And that will provide another couple of stories later on.

But, getting to today’s story – I spent many a lunch-hour buying parts at my friendly local Chevrolet dealer, Boehmer Chevrolet — BTW, whom GM cancelled their franchise after 95 years(!!!) of faithful loyalty. And that is yet another story.

I’d heard of a guy, Mark Webster, for years. He was a legend in our little town. He drove a garbage truck. And he worked hard every evening and every weekend in his home garage working on cars, mostly performance cars. He eventually earned a service technician job at Boehmer Chevy and later at the Corvette Corral in Highland Park, IL.

So, it was an honor when he befriended me. He introduced himself at the Chevy parts counter, then days later, stopped by my machine shop. I loved working on cars and so I soon frequented his “Fast Lane, Karz By Mark” garage. He built engines, lifted trucks, learned paint and bodywork, some of it fueled by Old Style beer.

And so he was entrusted to maintain, and later repaint, and later repair a local’s 1969 Le Mans Blue L-88 coupe. One of 116 L-88s built in model-year 1969.

Mark was pretty much unimpressed and jaded about most cars, but he was wide-eyed about this ’69 L-88. Well, after his eyes stopped burning – you could not stand to be in the garage with it idling, even with the garage doors wide open. Your eyes burned and watered. You risked florescent light tubes falling out of their overhead fixtures from the exhaust note ultra-bass. It was touchy to start from cold. It ran hot.

But on the open road, did it ever GO! Mark took me for a ride on a very HOT, very humid day. And BTW, Mark was a huge man, well over 6 foot, well over 300 pounds, size 16 shoes. People said my L71 Corvette really ‘pushed you back in the seat’. Well, the L-88 FORCED you back in the seat — way more. He shifted at about 7,000 rpm. It accelerated BRUTALLY, even on that hot, humid day, even with big Mark and skinny me on board. That L-88 made my L71 feel like a plush, smooth Cadillac. I was in awe, but of course did not admit it.

The L-88 was rated at 430 hp, but that was merely to set it a notch below the 435 hp L71 in spec sheets and discourage the uninformed that otherwise would buy the biggest hp Corvette on offer. In ’67, the first year the L-88 was offered, Chevrolet mandated a credit ‘option’ that deleted the heater/defroster in order to discourage street use of the L-88. And with very good reason. This delete ‘option’ is often mentioned with respect to the ’68 and ’69 L-88s, but in researching this at the interesting Corvette Action Center website, https://www.corvetteactioncenter.com/specs/l88/ there is no mention of the allegedly mandatory heater/defroster delete ‘option’ in ’68 or ’69 — it was only mandatory in ‘67. In 1969, 116 L-88 Corvettes were built. All ’69 L-88s had the following options:

F41 Heavy duty Suspension
G81 Positraction
J50 Power Brakes
J56 Special heavy duty brakes
K66 Transistorized ignition
L88 engine package

99 cars got the M22 close ratio, heavy duty 4 speed — with the new MA6 10” clutch in roughly mid-1969.
17 cars got the M40 Turbo 400 automatic.

The L-88 made more like 500 – or more – gross hp. It had aluminum heads, primarily for a substantial weight savings, roughly 80 lbs off the front of the Corvette, and later in ’69, the L88 came with improved flow, “open” combustion chambers. The L88 had a much more aggressive cam. At .540/.560”, lift wasn’t that much more than the L71 cam (with .500”/.500” lift). But L88 valve timing was much more aggressive, with lots of overlap, where the intake and exhaust valves are both open at the same time. That caused the very stinky, eye burning exhaust – lots of unburned fuel pumped out the exhaust at low speeds – and the very lumpy, lopey idle. The L88 had higher compression, about 12.5:1 for the earlier closed chamber version, and about 12:1 for the later open chamber heads. This was partially to compensate for the late intake closing valve timing that murdered low-end torque. The radiator shroud was deleted to allow greater air flow through the radiator – at high speed, but this hurt cooling at low speeds. The L88 package included a taller big-block hood, with cowl induction, and the air filter stuffed up in the hood. All this added $1032 for the L-88, plus another $880 for the other options listed above, to an already expensive $4781 ’69 Corvette coupe.

In my experience both the L71 and L88 were difficult to start in cold weather. The transistor ignition worked to 7000 rpm or more, but those big engines, often using heavier oils, like straight 30-weight (and some even used straight 50-weight), did not crank over very easily when cold. With stiff L88 valve springs, flat tappet lifters, and ball-stud rockers there was a lot of valve train friction. Even with all the spark plugs removed, it took about 80 ft-lbs to rotate an L-88 with a torque wrench on the damper bolt. So cranking over an L88 drew a lot of current from the battery. When you draw a lot of current, the battery voltage drops.

And big GM engines got the ‘high-torque’ starter motor. These had fewer and heavier gauge field windings, practically a short circuit, and a larger diameter armature. They spun the engine faster during starting, which was good for a stronger vacuum signal at the carbs, but it drew even more current from the battery, further dropping battery voltage.

So, with these high loads, battery voltage dropped during cranking and the sparks from the vaunted K66 ignition became visibly feeble. And what was the first thing drivers did when an engine wouldn’t start right away? Pump the gas pedal again (and again)!
And then you had a badly flooded engine, spark plugs wet with fuel, that drained off ignition energy – result: NO sparks. No start. Better keep your L88 Corvette in a warm garage, with a big, fully-charged battery, and maybe jump it, too.

The L88 I rode in and worked on had the four speed M22 “Rock Crusher” trans. The M22 was allegedly stronger and noisier than the M21 because there was less helix angle on the gears inside. Maybe there was a little more gear whine than my M21 had, but it certainly wasn’t objectionable and I love a little gear whine!

Sum total? What was the L88 really like? A real, hairy beast, a monster. And fast! But like a beast, it smelled really bad — if you could get it started. GM was right to strongly discourage street use. But the L88 was and is legend.

A few years ago, I went to the Bloomington Gold Corvette event in Indy. The show featured a 50th anniversary celebration of the ’69 L88s. I attended a couple of the seminars. One of them was a talk with L88 racers and owners. Some of those owners bought them new, as street cars. 50 years later they spoke with huge excitement and enthusiasm about their L88 ownership, as though their memories happened just a few days ago, as if they were still 20-something young men. And me? After 40+ years, I remember my one and only L88 ride the very same way!