MGB with a Camaro 3.4 L V6

1974 MGB with a GM 3.4 L L32 V6

BMC British Automobile is a company located in Isanti, Minnesota that restores and works on British cars. Although they install several different engines into many British cars they are best known for installing GM V6 engines into MGBs.

1974 MGB with a GM 3.4 L L32 V6

This 1974 MGB received one of BMC British Automobile’s conversions. They installed the 3.4 L L32 V6 and five-speed manual transmission from a 1993-1995 Camaro/Firebird using their custom mounts. This increased the car’s power from 87 hp and 103 lb-ft of torque to 160 hp and 200 lb-ft of torque.

1974 MGB with a GM 3.4 L L32 V6

1974 MGB with a GM 3.4 L L32 V6

The 1962-1980 MGB require different parts lists since body and cooling systems vary. Even air conditioning changes will cause the PCM, alternator, and ignition system to change locations and requires a different wiring harness. This is why BMC British Automobile keeps custom build lists according to customers’ requirements.

1974 MGB with a GM 3.4 L L32 V6

1974 MGB with a GM 3.4 L L32 V6

If you are interested in increasing power in your MGB you can send it to BMC Auto or you can purchase one of their MGB 3.4 L V6 swap kit. They also informed us they are developing a V8 conversion kit.

1974 MGB with a GM 3.4 L L32 V6

1974 MGB with a GM 3.4 L L32 V6

Source: BMC British Automobile FB page (more photos)

7 Comments

  1. MOPARfan

    So it’s nearly 2 times bigger than original inline 4, yet it makes less than 2 times more power? The Smoking Tire has a video of Supercharged MGB GT, which made 112 rwhp. And I doubt that this thing will be much faster than that one, even though it has more power, since V6 added weight.

    • Your right this would weigh more due to it being a newer generation. That 1967 GT Matt says weighs 2,150 lbs with some online sources said up to 2,190 lbs. This 1974 roadster weighs 2,315 lbs. But a similar year (1967) roadster weighs 1,920 lbs due to it having no hard top. So a roadster model with the V6 swap in the same generation would be very close in weight with double the power.

    • peter

      MOPAR, it’s nearly twice the displacement, and it’s nearly twice the horsepower. Also, pretty much twice the torque. I don’t see a problem.

    • Hi MOPARfan,

      The V6 weighs about 20-30 pounds Less than the MGB driveline, not more. When we are done with these, we switch the rear end gears out from the 3.909:1 to either a 3.31:1 or 3.07:1 plus we go to a 0.73 5th gear on average. At 60 MPH (2,000RPM @ 60MPH), you can drop it back in to third gear and move around traffic extremely fast or if you want, leave it in 5th gear and accelerate around the Supercharged 112BHP MGB. 🙂 We have had many people drive these after driving some of the MGB V8 cars and find these very comparable- some quicker. It may have 25% less cylinders than the V8 but that does not mean 25% slower. Due to fuel injection and gearing, the fuel economy is better than the stock MGB and for the average $4k supercharger bolted to an engine that was built for the supercharger at another $3k++ with a 5-speed conversion for around $4k, you can expect to have a car that lasts half as long, gets half the fuel economy but at least it is still the Austin ‘B’ series engine. The ‘B’ series are a good engine but everything has its limits, the popularity of the V6 conversion.

    • Durant,

      Let’s make a comparison:
      MGB Supercharger from Moss: $4,300. Average 5 speed conversion that is rebuilt and ready to installs appears to be around $4,000. If you install a supercharger on an old engine, get ready to see it give out within a few thousand miles. Since the engine is not built to take it, it will cost more than the average MGB engine rebuild. Right now, not including the engine rebuild, I have already named over $8,000 in parts also not including new hoses, heater valves, radiators and other things that it will need.

      Compared to the average V6 conversion, a DIY’er will have about $7,000 between a rebuilt T5 five speed, a used engine and all the bits and pieces to install it.

      Everyone has a different requirement and different expectations but to give ‘as close to’ apples to apples comparison, you get the same weight, TWICE the torque which equals cutting the 0-60 time in half, a reliable car that gets better fuel economy and a lower engine speed meaning the car give powerful but more relaxed driving.

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