The SCM Corvette by the Numbers

acd9956729a0f04e8a8354e79bae68cb

Decoded, the “period-correct” engine is a 1967 low-performance 327 for use in Powerglide-equipped pickups

Chassis Number: 30837S105613

By Colin Comer

Last month, I explained the basics of muscle car decoding. This month, I am going to see if our esteemed Editor Martin pulled a rabbit out of his hat when he purchased the SCM 1963 Split-Window Corvette, or if he botched the trick.

When he, along with SCMer Dave Stewart, bought the coupe last year, it was represented to Martin as being in its original color combination (Sebring Silver over black), with a non-numbers matching, yet reportedly period correct, high-performance 327 V8 and the original-to-the-car 4-speed transmission and rear differential. The purchase price was $33,000. Since purchase, Martin has spent approximately $3,000 doing what we all do with a “new” car—deferred maintenance and the ever-present “while we are in there” repairs. Martin reports the car runs and drives very well and seems quite smitten with its appearance and cosmetic condition.

What follows is a basic pre-purchase inspection, done, in typical red-mist SCMer style, several months post-purchase. My main goal is to determine if the car has the original drivetrain, tags, correct colors, and trim. The next step, which is beyond the scope of this article, would be to do a thorough inspection of body, chassis, interior, and secondary components. A special thanks to SCM General Manager David Slama for doing the yeoman work of taking the ’Vette to A&P Specialties, where owner Alan Blanchard, who looks after the SCM 911SC, put the ’Vette into the air, and removed the valve covers to get us the info we needed.

The SCM ’Vette is S/N 30837S105613. This decodes as 3=1963, 08=Corvette, 37=Coupe, S=St. Louis production plant, and the sequential VIN of 105,613—the 5,613th 1963 Corvette built. Looking at the trim tag under the glove box, I find the body production date of D4—translation, December 4, 1962. Using published production by month, this makes sense, as the last car built in December of 1962 was S/N 105972, 359 cars later.

The trim tag provides the paint code of 941A (Sebring Silver), and trim code of BLK, for black standard vinyl. Both the trim tag and VIN tag are original, not reproductions, and are affixed properly, appearing never to have been removed from the car—all very important. So this car is in fact in its original color combination. So far, so good.

Under the hood, I started by checking the casting numbers and date codes on the block. These are very hard to falsify, unlike the stamped numbers on the machined pad on the front of the block. The casting number on this block is 3892657.

Looking this up in a Chevrolet book, I find this is a generic casting number for a 1967 small block with various car, truck, and displacement (302/327/350) applications—but no Corvette fitments. The casting date code is B127, February 12, 1967.Uh-oh. Houston, we have a non-correct block in a Corvette.

Moving forward, I check the numbers on the front pad of the engine block. Although easily (and commonly) restamped by unscrupulous folk, it is still worth a look. What should be present are two sets of numbers. One set is the last six digits of the VIN (hopefully matching the VIN of the car), the second set is information as it pertains to the engine build info—engine assembly plant, assembly date, and a two-letter engine suffix code denoting the original specification.

This engine has no VIN on the pad, as it would if it were an original Corvette block (passenger cars and truck motors often had the VIN stamped in other locations), but does have the stamp V0414YH. Decoded, it breaks down to V=Flint engine plant, 0414=April 14 engine assembly date, and YH=327, low performance, 220-hp, Powerglide automatic-equipped engine for use with A.I.R (Air Injection Reactor) in C10–C35 Chevrolet pickups. Hmmmm. No wonder my truck wouldn’t start last week; somebody put the engine into Martin’s ’Vette.

Next I checked the cylinder head casting numbers and date codes, both under the valve covers. Casting number for both heads is 333882, and both date codes are identical at I304. The casting numbers tell us the heads are 1970–80 350/400 low-performance, small-valve passenger car heads, with a date code of September 30, 1974.

Last stop under the hood is the intake manifold and carburetor. Always looking for the silver lining, I am still optimistic we will find something original. Alas, today is not the day. With a casting number of 3890490, the intake is a 1966–1967 327/350-hp Nova/Chevy II/Corvette piece—a desirable part, but not correct. The carburetor is a new Edelbrock aftermarket one, similar to the one Jethro may have just screwed on his monster truck last week. One of the wonderful things about the legendary Chevy small block V8 is parts interchangeability. Unfortunately, whoever built this motor took full advantage of this fact.

Without any original paperwork to go on, we have no idea what drivetrain the car came with originally. However, like any good mystery, we do have clues. The tachometer appears original and has a 6,500-rpm redline, used only in 340-hp carbureted and 360-hp fuel-injected cars. Under the hood, there are no signs of a fresh air intake in the core support, nor any mounting holes for the huge fuelie air cleaner. If I had to guess, I would say this was originally a 340-hp car. Further detective work would tell us more.

The correct, original, early 1963 aluminum Borg-Warner T-10D1 4-speed is present, and the differential is original as well. This is important, as later ’63 ’Vettes switched to a cast-iron Muncie M20 4-speed, and early aluminum T-10s are tough to find.

The big question: At $36,000 so far, did Martin get a raw deal? Not necessarily. Non-numbers-matching examples of 327/340s in this condition can bring close to $50,000, so Martin is still safe. However, a little pre-purchase due diligence would have told Martin exactly what he was getting, which might have helped him in his negotiations.

My advice for the future of the SCM Split-Window ’Vette is to find a correctly dated early 1963 3782870 block, correct 340-hp heads, a correct intake manifold and carburetor. I’d send the works to a great Chevy engine guy and have him do his magic. The end result would be a correct, strong powerplant that adds value to the car—and performance, as my guess is the current engine is putting out no more than 250 hp, and maybe less. I estimate the total cost of building and installing a correct engine would be under $10,000—about the same as a major service on any late-model Ferrari.

All said and done, Martin would have a reliable, correct, but non-numbers-matching Split-Window that runs like a bear for under $50,000. Not a bad deal in my book, and worth perhaps $60,000–$70,000. Until then, I say keep the numbers dorks from looking under the hood and keep driving.