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MG MGB GT V8 Factory Originals Technical - Performance Specs

Hi, does anyone have any basic 0-100 or 1/4 mile times for a standard (if there is such a thing) V8 MGB conversion? All i could find is for the orignal GTV8s...

I am contemplating it for my '79 B, but would like to get an idea of the performance to be expected to deem whether it is worthwhile...

Any help numbers (kw/hp/0-100/etc) would be appreciated. I don't like being beaten off the line by a Hyundai, but would be worse if i had spent time/effort putting in a V8 for the same to happen!


That will vary widely based on car set-up, engine output, trans, track location, condition and most importantly driver ability.

With my new driver lack of skills, stock rear, tires and a mild 302 with T5 I pulled a tire schreeching 13.8@102mph, car had more in her, but traction and my skills were limiting factors.
Larry Embrey

There are now so many conversions and BHP variations but if you were to tell us which you were contemplating, someone would have the answer you need.(70 -100 mph may be more interesting than 0 - 60).


Yes, the most useful yardstick is the acceleration in one gear, as little driver skill is involved. A standing 1/4 mile or 0-60 mph time is so dependent on the skill of the driver, it is really meaningless. I always think 50 - 70 mph in fourth is good as it replicates an overtaking manoeuvre on the road.

As the others said, you would need to tell us your proposed set-up. Size of engine, modified or not, carburation, transmission, rear axle ratio, wheel & tyre size. Ken Costello used the standard tune Rover engine which gives about 20 bhp more than the factory MGB V8. I'll try to look up what those cars achieved when I get home.

Mike Howlett

Last ran 15.1 sec 1/4 at 92mph with a 3.5ltr SDi spec motor with standard cam and heads (SDi)and a 390cfm Holley. 3.07 Diff. Maybe 180-190ish bhp. Lots and lots of passes made, needs more bhp to go any faster.
Hope this helps. J...
John Maynard

Here is a link from the 1999 V8 Convention. At the bottom of the page are the drag strip results. Speed results only they had trouble with the timing device. This should give you an idea how diferent V8 mods will perform. The other major factor is driver.
Jim Miller

i dont know if anyone else knows of this site (most probably) but as we're on the subject i though i'd just quickly plug it.

pretty handy
J P Connor

<<Speed results only they had trouble with the timing device. >>

Hi Jim,

The trouble with the timing device was that we didn't have one for the 1/4 mile runs. Just a State Trooper with a radar gun. No tickets given. :)

Now here's a strange thing. I have an "Autocar" test of the Costello GTV8 (150 bhp DIN @ 5000 rpm, 201 lbs.ft torque @ 2750 rpm) and a "Motor" test of the factory car (137 bhp DIN @ 5000, 193 lbs.ft @ 2900). Both cars used the same transmission and final drive.

Both gave almost identical performance, so either the Costello was on an "off"day, or the factory car was better than normal. The 0-60 time for both was 7.8 secs Costello, 7.7 Factory. The 1/4 mile time was 15.8 secs for both, terminal speed 83 mph.

To put this in context, the times for a 1970 UK spec (no emission equipment, twin SUs) chrome bumper mgb roadster ("Motor" road test) are 0-60 in 11.0 secs, 1/4 mile 18.2 secs. No speed given. In my limited experience, that particular car was a lot better than many, so there are considerable differences between the 1800 and the V8.

Mike Howlett

This thread was discussed between 01/06/2004 and 02/06/2004

MG MGB GT V8 Factory Originals Technical index

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