Project Idea: eBay-Sourced Corvette Diesel Commuter
As my online handle “Mad_Science” might suggest, I have some experience with the world of science and research (I once had a remote control rabbit). Funny thing about research: you can’t sell it. Well, not in the traditional sense. With a conventional product or service, the buyer pays upon delivery. In the case of research, it’s really the opposite. They pay you… and you receive a report, or something, eventually. With that in mind, we’re kicking off a series of Project Proposals. We’ll propose some cockamamie scheme, then take the next step and show you just how you could get it done.
To get things rolling I propose we grab a clapped out C3 Corvette, drop in a 6.2 or 6.5L Detroit Diesel and turn it into a great long-haul commuter. The crazy part is how one can use GM parts bin engineering to make it surprisingly easy. Let’s see what it takes to make Project Smokeyvette a reality…
The idea was born from my previous commute: 41 miles of full-speed reverse commute in Los Angeles. While my WRX and Falcon worked just fine for the job, the idea of a purpose-built commuter that wasn’t some tiny dorkmobile was very attractive. “Reasonable_Science” would probably just run out and pick up a TDI VW, but where’s the fun in that? Let’s see if we can’t find something more fittingly unique.
The ’69-’82 “C3” Corvettes can be called a number of things, but “dorkmobile” isn’t one. It took nearly two decades, but the styling’s grown on me. The best part is that they are widely regarded as the worst Corvettes ever, most critically by Corvette aficionados. Stripped of their Quaaludes at the roller-disco context, they’re a decent platform from which to create a shapely cruiser.
The C3 arguably best personifies the Malaise Era, declining from a late-60s high point of style and horsepower to a 165hp plasticized parody. This is to say, no one’s going to shed a tear when we rip out that smog-choked big block and drop in an oil-burner. With no pretense as a serious corner carver, we’ll free ourselves of gnarly suspension upgrades save just getting things fixed. The end goal is a comfy, stylish commuter getting in around 40mpg.
With that in mind, let’s go shopping. In California, 1975-and-older vehicles are smog-exempt (later if SB 1224 were to pass), so we can start our search there. The best candidate would be clean-bodied with a blown motor, but since this is Hooniverse we’re just looking for the cheapest serviceable example. Numbers matching is for Sesame Street viewers. We’ve come up with a couple of options:
If we pretend for a second that California SB 1224 passed (moving smog test exemption up to 1980), this ’77 makes a lot of sense. It’s a more-or-less intact shell with handsomely faded blue paint. Whether or not glass comes with the car is unclear, but for $225 (with no reserve) as of this writing, we can afford to replace it all.
In significantly less hopeless condition we have a ’69 with a new interior and paint, but no motor. Ok, I lied; it’s actually got two motors: a boring GM Goodwrench 350 and the (presumably dead) 350. Neither is installed, so let’s just unload them and fatten our project wallet. At a little over $3,000 with the reserve unmet, it could get pricey…but it’s probably worth avoiding sanding GRP yourself.
This ’72 has been sitting for 10 years with a shot 454 (water in oil) and an exterior appearance that’s decidedly not HOA compatible. It does come with a four speed and updated suspension bits. It’s got 100k on the odometer and a $4,500 price tag as of this writing. We’ll call her “Hoonilocks.”
Detroit Diesel 6.5 Engine
Following up on that, it’s motor time. The Detroit Diesel 6.2 and 6.5L motors were designed in a fuel-crisis scarred era to focus on efficiency, not crazy power. In a military CUCV the 6.2 can pull high teens to low 20s mpg, so imagine what it can do with 1,500 pounds less weight and no Duplo aerodynamics. While a turbo 6.5 would pack a better punch, a normally aspirated 6.5 will give us a bump over the 6.2 but keep the engine compartment less cramped and hot. This example is a complete “drop in and go” from a ’91 one-ton GM Van that was running as of yesterday. Not bad for a $1950 asking price.
To get the most of our miserly diesel, we need to keep the revs low. The first step is an overdrive transmission, specifically the heavy-duty 4L80e already found behind numerous oil-burners. Depending on your risk tolerance and faith in GM powertrains, you could pick between this re-manufactured unit for $1,605/1,790 (start/Buy-it-Now).
Or this $895, 6-month warrantied, 95k mile used example from a totaled van.
Since our Corvettes date from an era where computer was defined as “one who computes”, we’ll need to pick up a stand-alone transmission controller. This unit from TCI Automotive does the job for $558.88.
The overdrive automatic gets us a long ways there, but we need that diesel lump chugging at roughly 1800rpm for best efficiency. Pluggin the .75:1 overdrive of the 4l80e and a set of roughly 27″ tall 225/70 R15 tires into the Vexer Gearing/tire size calculator, a set of 2.72:1 ring and pinion gears to get in the sweet spot. Unfortunately all we can find are 3.08:1s, either for $400 new,
or $99.99 used:
If we bump up to a set of 235/70 R15 Radial T/As, we’re just a notch over 2,000 rpm at 75 mph. $150 each.
Adding it all up and ignoring the minor details, you’re looking at $4-$5k in upgrades to a roughly $4-5k car. Depending on how much gets DIYed, you’d be realistically looking at $15-20k to make Project Smokeyvette a success. There’s something satisfying about the idea of showing up to a Corvette meet in a rough-looking, smokey, clattering example of Detroit’s decline, preferably smelling of french fries. Would you hoons dedicate valuable research dollars to such an endeavor?
This post is part of eBay Finders, a new partnership that presents collections of items curated by a carefully selected group of motors experts. Meet more of the Finders at ebaymotorsblog.com. #eBayFinders