Can I swap my Chevy Blazer’s V-6 for a V-8?

Question:

We have a 2001 Blazer 4x4 four-door as well as a 2001 Blazer 2x4 two-door, both with automatic transmissions and 4.3-liter V-6 engines.

We have heard more than once that GM 350 V-8 engines can be transplanted into these vehicles without major modifications or expensive conversion kits. If so, we're asking you and your readers if anyone knows of a company that specializes in providing adapter/conversion kits to do this.

Also, we need sources that might provide conversion kits for wiring harnesses and the addresses of such sources. Their locations need not be in our state.

Presently our tentative plans include—if a V-8 engine can be installed —to use a manual transmission and to modify the motor to use a carburetor, but still retain the pollution control devices from a donor car. Ultimately these vehicles will not be high performance.

Answer:

There are a number of kits available to do what you are contemplating and they are not horribly expensive, depending on your idea of expensive. The job takes a fair amount of time and careful shoehorning—perhaps 100 hours or more—but it is possible to do it without extensive modifications to the chassis or body of the car. If you choose to have it done, I’ve read that it could cost in the neighborhood of $12,000.

Most of the kits specify which engines can be used with them, and kits are available for two- and four-wheel drive vehicles, and automatic as well as standard transmissions. One important consideration, though, is what is involved in meeting the smog requirements of the state of Idaho. Some states will not allow you to adapt an earlier engine than your car's model year, so check with the authorities before you lay down your money.

If you are considering doing the job yourself, you should purchase one or both of the available books on the subject. The first is the Chevrolet S-10 Truck V-8 Conversion Manual, and the other is Chevrolet TPI and TBI Engine Swapping. These books are available through Amazon, or you can order them from Summit Racing Equipment (listed below).

Most GM small-blocks will fit into your vehicle, but some of them would be easier than others to hook up. The easiest would be the Camaro or Firebird mills out of the 1988-92 models. That’s because their accessories, hoses, and oil and temp sending units work with the Blazer. However, the Corvette LT1 engine would not be a good fit because the exhaust manifolds won’t work, the accessories are in all the wrong places, the oil pan won't clear the cross-member, and the wire harness is difficult to adapt to your application.

Going to carburetion instead of fuel injection would simplify things a bit, but again, be sure to check Idaho’s smog laws because such a setup would not pass the pollution standards for a car made in 2001 in many states. Also, going to a standard transmission means that you will need a clutch pedal and hanger plus a bell housing that is set up for a standard gear box.

The T5 and NV1500 transmissions GM used with their smaller engines will not be able to take the torque of a big V-8, so you will want to go to the NV3500 five speed gear box from the 1990 and later 4,3-liter S-10 engines. Another possibility is to install a T-56 six-speed tranny from a 1993-97 Camaro or Firebird. That would be more work, but would make an outstanding unit for your Blazer because of the gear ratios. You will also want to consider going to a beefier differential if you are going to be pushing the two-wheeled vehicle hard.

A final thing to consider is cooling. The standard-issue radiator in your Blazer may be just adequate for your new engine, but you will probably want more than “just adequate.” The 1985-89 Corvette radiators are ideal because they have skinny 1 36" cores which will allow room for an engine-driven fan with the correct pitch. Contrary to what you may have been told, push fans and aftermarket electric thin-profile fans do not cool as well as the mechanical fan that came with the engine. Custom radiators can be built to your specification as well.

Adapter kits and components are available from:

Summit Racing: https://www.summitracing.com/

Hedman Hedders https://www.hedman.com/

Advance Adapters: https://www.advanceadapters.com/

Stealth Conversions https://jagsthatrun.com/

TD Performance https://www.hedman.com/Trans-Dapt-Performance