V6 to V8 Engine Conversion for a Chevy
Small-block Chevy engines have been shoved into everything from Ford street rods to Dixie Chopper lawnmowers. Given the availability of V6-to-V8 swap kits, replacing an anemic six-banger with a fire-breathing small-block is practically a bolt-in ordeal. This path is well-traveled and gets easier with every year of development. This project is more about choosing the right components than actually putting them together.
Before swapping anything out, you’re going to have to know what kind of engine to install. It’s not going to do you much good to have a 500 horsepower street-devastator only to find that it’s impossible to drive because of state smog laws. Many V8 conversions are surprisingly legal in most states, but with a few basic caveats.
In most states, the engine used cannot be older than the chassis for emissions compliance. If your state laws allow you to put a carbureted engine into your truck, then do it. Unless you absolutely need/want fuel injection, a carb is going to be the fuel mixer of choice for cost and simplicity.
There are at least a dozen different companies that make V6-to-V8 conversion kits that include motor mounts, exhaust headers and sometimes a transmission mount. Advance Adapters, TD/Hedman Performance, Hooker and Stealth Conversions all make excellent kits, but don’t for a moment think any of them are complete. These kits give you the parts you’ll need to physically fit the engine into the truck, but you’re going to have to supply everything else. This includes any electrical components, cooling hoses, radiator and engine accessory drives.
The most popular transmissions for this swap are the three-speed TH350 and overdrive 700-R4s. The good new is that many V6s already come with the decent 200-R4, but this transmission should only be used with a bone-stock small block. Anything more powerful will rip the 200-R4 to pieces. Don’t even consider using a 700-R4 older than 1986 or one that originally came behind the 2.8L V6. The older transmissions aren’t strong enough, and 2.8L 700-R4s have an engine-specific bolt pattern that won’t work on a V8.
This is a pretty straightforward engine swap. S-10s and similar mini-trucks have plenty of room for a V8, and Camaros have always had a V8 option. Simply replace the stock mounts and exhaust headers with those from your kit, drop the engine in and hook everything up.
Of course, how complicated this will be depends on your application. Dropping a carbureted 350 into a 1985 S-10 is a no-brainer, but it gets a little more complicated when you’re talking about putting a 2009 LS7 into a 2002. Later-model fuel injected engines may require stand-alone fuel management of transmission management computers. Accessory drives, alternators, A/C compressors and power steering pumps will often transfer between V6s and V8s of the same model year. Fuel injected engines will require a dedicated high-pressure fuel pump and system.