Welcome to our resource for MG Car Information.



MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB GT V8 Factory Originals Technical - Real Performance Figures

What kind of hp does a v8 put out with out too much modifying? What kind of 0-60 / quarter mile times can you get out of one???
Ben Davids


My 4.6 with Stage 1 heads should produce 270bhp, unfortunately the rolling road I use keeps breaking down so no official figures yet. 0-60 about 5secs if you can hang it alltogether but not much of a chance on UK roads. However car will pick up in 5th from 750rpm and take you to 140mph with no problem if we didn't have a speed limit.

I am considering a midget with 350bhp some time in future.

Paul Wiley

I have been using a "Car Test Program" which is a performance simulator.

There are MGB's and an MGR in its 1,000 car database.

The standard MGR with 190 hp at the engine came out at
0-60mph 6.5 secs
Top Speed 128 mph
Quater mile 15.0 secs @ 93.1 mph.
Can anyone confirm how accurate these figures are.

I have a link and a small write up on my website.


Nick Smallwood

Can I ask what type of back end you're running all that power through?


RV8 Clutch, from then on SD1 - original UJ's got stripped so replaced with greasable - usual Koni set up lowered.

I would add that I use this car everyday for work.

Paul Wiley

My 3.5 Roadster with a fully balanced engine, decent head, Hopkinson "special" cam , 390 double pumper with a 7 psi fuel pump and RV8 headers into a dual balanced exhaust plus lumenition gives just over 200 bhp at the wheels on Sigma Engineerings rolling road. The car only has about 4500 miles on the engine so there may be a little more to come. All I can say about the performance is that it goes bloody fast!
My 3.9 "factory" GT, with a 600 double-pumper similar engine spec and RV8 headers into a single system gave around 215 at the wheels on the same rolling road - BUT- it only has a couple of thousand miles on it. It goes fast enough, tight as it is, to seriously piss off BMW owners.
Sigma know what they are doing and if you need a car set up, ask them. They are at Gillingham in Dorset - and no I have no connection to them - apart from giving them money!
robert pulleyblank

I'm a Sprite driver now, but having put a V8 in a '76 Datsun Z.
7.5/1 comp
'92 T-5 tranny
Wieand 144 blower 6psi
block huggert headers w/ 3" exaust
edelbrock rpm cam
52k miles my daily driver @23mpg
11.85sec @ 121.3
my '62 sprite is destined to have a 1275cc w/ a blower.


The simple answer to your initial question is that the V8 in most forms can produce far more torque and power than the chassis can handle. This means it isn't the engine you have to work with but the chassis so you can get that power down to produce the performance.


I would not argue with the acceleration times as I recall that a low mileage example tested by Autocar was doing the 0-60 in 6.9 secs. Top speed is another issue and this test car was able to reach a mean of 135mph. Taking the known performance of the standard GTV8 and the power of it's engine I calculate that the extra power of the RV8 should mean that it would reach 138mph. Allowing for a slightly less efficient shape and less than ideal gearing for maximum sped the 135 reached by the Autocar test car seems representitive.

My own car at Bruntigthorpe some years ago was able to pass through the timing beam at just over 142mph repeatedly with no wind and an uphill first third of the run. This with a wheel recorded power of just under 190bhp.

Roger Parker

This thread was discussed between 05/10/2000 and 21/10/2000

MG MGB GT V8 Factory Originals Technical index

This thread is from the archive. The Live MG MGB GT V8 Factory Originals Technical BBS is active now.