Should You Rebuild or Replace That Tired Corvette Engine?

Frequently Asked Questions About Corvette Engine Replacement

When you take on a Corvette restoration project, one of the major projects (but not always the biggest project) is the restoration of the engine. This is not only a matter of your Corvette's power and performance - with older 'Vettes the engine is a critical piece of the car's history. Originality is absolutely critical, but often difficult to achieve.

The choice before you when you consider your engine can be complex, even before you consider how much it's going to cost. The first big decision is whether you should rebuild the engine that's in the car, or go out and buy a new one. Here are the factors to consider:

What does “Numbers-Matching” mean, anyway?

Restored Corvette Engine
This is a great example of a well-restored Corvette engine. Everything is clean, painted in the correct colors, and absolutely bone stock. This engine bay is worth far more than any aftermarket engine could make it. Photo by Jeff Zurschmeide

At the factory, the original engine should have been stamped with the Corvette’s serial number (or VIN, after 1981) on a flat boss on the block. There’s also a date-of-manufacture on the engine and many other parts. Some people say that having the correct dates of manufacture is good enough, but others insist on having that matching VIN number on the engine block. Here’s the rub: anyone can buy a blank engine block and have the boss stamped with a particular Corvette serial number.

Is it important to have the original numbers-matching engine in my Corvette?

Rochester Fuel Injection
This is a "Fuelie" engine from the 1950s and early 1960s, as used in the Chevrolet Corvette. The system used Rochester Fuel Injection, which was a mechanical system that yielded 360 horsepower from a 327 cubic inch V8 engine. This engine adds tremendous value to any Corvette, as long as everything about it is original and the car actually came from the factory with fuel injection. Photo by Jeff Zurschmeide

That depends not only on what the state of the Corvette market is today, but what you think it will be in the future. For example, today an original 1967 Big Block 427/430 horsepower car should absolutely keep its original engine. A 1998 C5 base model, not so much. Here's the bottom line: if you have the original numbers-matching engine installed at the factory and it's not broken into little pieces, it's never a bad idea to set it on a stand and put it in the back corner of your garage, while you drive around with a new engine in the car.

I want more horsepower! Should I rebuild my old engine or buy a new one?

LSX454 Corvette Engine
The LSX 454 is the most powerful crate engine Chevrolet has ever built, at 750 horsepower. Photo courtesy of GM

More power almost always involves making modifications (like increasing compression) to your engine, and those modifications cannot easily be reversed. If you want more power, you should buy a new engine in a box - you can choose your horsepower level from a catalog. Plus, it leaves your original engine in stock condition if you break the new hot rod engine.

My original engine is broken, what should I do?

Corvette Crossfire Injection
Corvette Crossfire 350 V8 Engine - this one is a basic 350 block with an early attempt at electronic fuel injection - these engines mostly need a rebuild when you find them. Photo by Jeff Zurschmeide

You can do two things – you can rebuild the engine with new parts or you can buy a replacement engine. If your engine block is still in rebuildable condition, you can put in a new crank, new pistons, new heads, and so on. If your engine block has a big hole in the side where the pistons came out, or it’s broken in two (or more) pieces, then you’re probably looking at finding a similar engine and making do with that.

Should I rebuild my engine myself or send it out?

C5 Corvette Engine Bay
C5 Corvette engine - this is a precision piece of equipment, do you really want to risk your investment on your garage skills?. Photo by Jeff Zurschmeide

Unless you’re a professional engine builder or you really want to hand-assemble your own engine, send it out. In fact, even if you really want to hand-assemble your own engine, you should still send it out. A quality engine rebuilder will send you back a finished, painted long block with a warranty for about the same price as getting the machine shop work done and assembling the engine yourself. You should be able to get a fresh rebuild on a sound small block for about $1200-$1500.

Can I buy a brand new engine for my Corvette?

GM Goodwrench
GM Goodwrench 350 engines are a great brand-new choice for your C3 or C4 Corvette. Photo courtesy of GM

The good news is that most small-block Corvettes were built with Chevy's 4-bolt main 350 cubic inch engine. These engines are readily available - you can even buy a brand new "Goodwrench 350" engine at any Chevy dealer. The Goodwrench 350 costs less than $2,000, and is rated at 195 net horsepower, but that quickly rises to 260 or better with the addition of a free-flowing exhaust and an aftermarket intake and carburetor. Avoid used engines - you don't know what's inside them, and neither does the guy selling you the engine.

With newer models (such as the LS series), you can buy those engines new from your Chevy dealer, but they'll cost more than the venerable 350. Obviously, less common engines are harder to find and not made new any more, so you're looking at a remanufactured engine for your 283, 327, 396, 427, or 454.

Visit the GM Performance Parts site for a complete list of factory-new engines for your Corvette.