How to power-tune an MGB GT

As I don't want to play around trying to get more horsepower out of the 1800cc engine, and as I won't convert my car to a V8 to keep it's original character, there are only two options, both in Stage 2 form: 1950cc or 2100cc...

2100cc Stage 2. Photo (c) by MGOC
Nice, detailed engine bay


It's simple: Increasing the cubic capacity means more torque, and that's why I want a 1950cc or 2100cc engine, the later being the largest capacity MGB 4-cylinder engine yet. Going for Stage 2 specification means a more powerful, higher revving and smoother engine. The 1950cc Stage 2 should produce about 115-120 bhp, the 2100cc Stage 2 approximately 135+ bhp, with loads of torque. But the 2100cc are not only achieved by a bore diameter of 85 mm, but also by stroking the crankshaft through offsetting the big end journals by 2 mm ! As this weakens the crankshaft, I'll probably opt for the more reliable option of 1950cc...

Photo (c) by MGOC
All you need for Stage 2 - and more (below): Gas-flowed cylinder head with larger 3-angle valves and hardened valve seat-inserts for unleaded fuel, HS6 AUD505M carburetters, special tuning inlet manifold, performance distributor, fast road camshaft, Duplex Vernier timing gears, Borg&Beck performance clutch, stainless steel tubular manifold, alloy valve cover, Lumenition ignition. I'll have the engine fully balanced, while fitting an electrical fan should make it more efficient. Maybe I'll fit an alloy sump, too.

I have not yet decided whether to buy an new engine or to rebuild and tune the original unit...

Doing most of the work myself might be the best way to get the 'right' engine. I intend to use my MG solely as a fun-car, but it should be able to cope with occasional city traffic etc.
Has someone built what he thinks is a powerful yet reliable performance engine? What about those MGOC engines?

All future work on the engine will be featured on these pages.

The book

How to Power Tune MGB 4-Cylinder Engines from Peter Burgess, SpeedPro Series, ISBN 1 874105 61 8

"Whether you want to go racing or have maximum street performance, the expert advice in this book will help you to build a powerful and reliable engine..."
This is what the cover text says, and it's true. I can definitely recommend buying this book if you think about tuning your MGB...
How to power tune MGB 4-cylinder engines, by Peter Burgess