MGB LS V8 Install Kit

This kit will enable you to bolt in a GM Gen 3 or 4 LS V8 into your Rubber Bumper MGB (1974.5 – 80) with minimal modifications or 1962 -1974 Chrome bumper MGB (once the firewall modifications are completed). Aluminum block LS V8s are recommended to save weight.

MGB 302 V8 Kit

Parts will arrive painted in Chassis Black, unless otherwise requested, with powdercoat options also available at extra cost.

MGB 302 V8 Kit

Kit price is only $2750 plus shipping & core charge.

(Front crossmember core charge is $275, this will be refunded when a good clean core is shipped back) It is highly recommended that you find a core or use your existing front crossmember, as cores are not always available.

Please feel free to contact us to order or to request more information.

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LS V8 Kit FAQs

Can my MGB handle the power increase?

Yes, as long as your MGB has a good & solid rust-free body.

How much power does the GM LS V8 make?

  • Power really depends on your parts list. 4.8 iron truck LS with aluminum heads and stock cam will start at 255 HP, 5.3’s make slightly more, 6.0’s about 345 HP and 6.2’s 400 HP in stock trim.
  • Corvette and Camaro versions LS1, LS6, LS2, LS3 and LS7 all make fantastic HP numbers.
  • All aluminum LS engines are recommended, as they are 100lbs lighter than the iron block LS.

For a budget aluminum block LS, take a look at the LM4 or L33 engines

Here is a link to the LS family of engines

How heavy is the LS in comparison to the stock B engine?

The stock B series MGB engine weighs in at 360lbs. A stock LS with aluminum block & heads weighs in close to 415lbs.
So only an increase of 55lbs.

What modifications do I need to do to install the GM LS V8?

(All modifications are covered in detail in the install guide.)

For a 77-80 MGB, 4 key areas will need to be ‘adjusted’.

  • The kit uses MGRV8 style headers, which means the inner fenders will need small cutouts (photos are provided).
  • You will need to slice the driver side footwell removing about ½ “strip to allow space for the huge GM bellhousing.
  • Depending on your accessory choice, you might have to re-shape the top of the passenger side footwell slightly to allow more room for the cylinder head.
  • The lower radiator panel will also need to trimmed back to allow the radiator to be as far forward as possible.

For the 74.5 – 76 MGB, per above, plus the radiator supports will need to be moved forward or removed and the radiator lower panel shortened as per the 77-80 MGB.

For 1968-74 Chrome bumper cars, in addition to the above, the firewall will need to be modified to be similar in dimensions to the later 1974.5 -80 MGB’s. 1962-1967 has a slightly smaller transmission tunnel, which might need tweaking slightly in addition to the above.

Can I buy a complete install package, including engine, transmission, driveshaft, radiator etc.?

Yes, we can supply everything you will need to make your LS V8 install a reality, please contact us for a tailor-made install package.

How easy is it to make upgrades to the GM LS V8?

The aftermarket support for these great engines is huge. Parts can be purchased from us or your local parts store, plus many internet mail order chains like Summit Racing Equipment or are available to suit your needs.

Can I purchase kit parts separately?

Yes. Kit parts can be purchased individually, but is much cheaper to purchase them as a complete kit.

For more info or questions, please contact us at:

Mantell Motorsport
Pete Mantell, Proprietor
2147 Co Rd 1100N
Sidney, IL 61877
Cell: 217-649-7717
email Pete
MGB 302 V8 Kit