Identifying a car can be a difficult task, and an L88 Corvette is no accept ion, the very first thing you have to look at, is the price of the car. In this day and age an L88 Corvette can easily run 100,000 dollars or more, and if you’ve located an Corvette for sale and the person selling the car is representing it as an L88, and the price is low “BEWARE” of a scam right up front, these are very rare and hard to find cars, and even a wrecked one can run 30,000 dollars or more.
Now down to the brass tacks, the first thing that I would look at is the engine codes, such as the RPO code and casting numbers to make sure that the engine is an L88, there are however some tell tail signs, keep in mind that not every L88 had the 3X2 carburetor option installed on it, this was an add on known as the L71 tri-power option, now an L88 is a 427 CID engine, that normally came with a single Holley 850 double pumper carburetor, so just because you don’t see a tri-power set-up on the car does not mean that it’s not an L88 427 car.
A true L88 Corvette is a rare find, so you can feel lucky if you happen to find one, also available was the L89 aluminum head option, that would shave 75 pounds of the front end weight of the car, if your lucky enough that the car that you plan to buy has a build sheet with it, you can know exactly what the car came with from the factory, but again this is a rare find in the classic car world.
On the engine the RPO code is located on a machined pad in front of the passenger side head, the RPO will tell you what year the engine was built, what engine it is, and usually what transmission was attached to the engine, it will also reveal what manufacturing plant built the engine, the casting number will also tell you what year the engine is, how many main caps it has and the horsepower of the engine, with the pro code you need to look closely because people have been known to machine and re-stamp these numbers, if the RPO code does not match the casting number in any way, be very leery of the deal that your about to make, ask a lot of questions.
When deciphering the RPO code on the front of the engine it helps to know how to read the stampings this is a typical reading for a 1957 – 69 RPO code.
1) The first digit represents the plant that the engine was built at
2) The next two digits represent the month that the engine was built
3) The next two represent the day that the engine was built
4) The last two are the suffix code
The suffix code is what will tell you what engine is in the car, and what options it has, below you’ll find a list of the codes for the 427 Engine.
Horsepower Transmission, Options Suffix Code
390 4-Speed, Hydraulic Lifters, Special Cam, 4BBL Carburetor IL
390 4-Speed, Hydraulic Lifters, Special Cam, 4BBL Carburetor, AIR IM
390 Powerglide, Hydraulic Lifters, Special Cam, 4BBL IQ
390 Powerglide, Hydraulic Lifters, Special Cam, 4BBL, AIR IR
400 4-Speed, L36 Engine, 3X2 Carburetors JC
400 Powerglide, L36 Engine, 3X2 Carburetors JD
400 4-Speed, L36 Engine, 3X2 Carburetors, AIR JF
400 Powerglide, L36 Engine, 3X2 Carburetors, AIR JG
430 M22 4-Speed, 4BBL, Special high performance cam IT
435 4-Speed, 3X2 Carbs, L71 Engine, Aluminum Heads IU
435 4-Speed, Mechanical Lifters, 3X2 Carbs, AIR JA
435 4-Speed, Mechanical Lifters, 3X2 Carbs JE
435 4-Speed, L71 Engine, 3X2 Carbs, Aluminum Heads, AIR JH