Stock MGB?
An MGB with an Engine Conversion?
Even some MGAs or Early MGBs:
An MGB with an Engine Conversion isn't complete without the correct Rear End Gear Ratio!
How about a 3.07:1 or a 3.31:1 rear end ratio in your MGB Steel wheel or wire wheel Tube axle?
Rear end gearing is not Mission Critical to phase one project completion for running, driving and getting the bugs out- So we suggest get the primary items dealt with, then come back the following year on some projects. However, once you have swapped out your gears, these will change your car as much as the engine conversion did! You will stay longer in each gear and likely STILL be quicker 0-60 with that torque! This will re-gear 4th gear engine speed to feel like 5th and your 5th gear will be a proper overdrive in just about every conversion we've had our hands in. As large torque V6/V8 engines with more than 200 foot pounds of torque engines that produce maximum torque between 2,000-5,000 RPM, this is a great way to go... Where it wouldn't work? Maybe if you've designed a short track car and you need to run 7,500 RPM all day- not a common point for street cars.
Stock MGB 1.8L 4 Cylinder? Yeah- we're talking to YOU too!
Although we offer these Especially for those installing Monster Torque in their V6/V8 engine conversion MGBs, they also work VERY Nicely in many Stock 1965 onward MGBGTs with tube axles, and 1968-1980 MGBs with the salisbury type tube axle in the right conditions.
Don't believe us? A short (and wrong) history of British Engineers and the accounting departments... If it worked on Narrow, curving British roads, between the hedgerows, going up and down hills, where speeds were generally kept lower, it must work well in America. Then some of them came over to the USA on Holiday, probably driving American cars not having realized that American cars have larger tyres and taller gearing to cut the engine speeds down for our Loong and sometimes boring stretches of road that most of us can relate to. In house, we've re-geared low engine output rubber bumper MGBs with 3.31:1 rear end gear ratios. This gives all four gears a slight overdrive feel leaving your car in first gear longer (but it doesn't make it feel too much longer!) and when in fourth gear, the car will feel nearly identical to an MGB with the electric overdrive engaged. A 3.31:1 rear end essentially gives fourth gear the near same effect (0.84:1) as a stock MGB overdrive (0.82).
What about an MGA with a 3.31 axle?
Fun Fact. An MGA can fit a tube type MGB rear axle! Make sure to read the section on stock MGB 4 cylinder engines as well.
What more to know: The 1500 is a bit underpowered, and if running a stock 1955-1967 MGA/MGB gearbox with the large gear difference between second and third gear, we would recommend a bit more power first. This upgrade will go from the stock MGA from the 4.3 or 4.1. MGBs of all years have a 3.91:1. For an MGA, we recommend the 3.31:1 in a tube type axle. There are great write ups online about switching out MGA rear axles (both "Disc" and "Wire" wheel rear axles) with late model MGB axles complete with the later/better brakes. Yes, we've done these conversions as well!
Who might want to consider sticking with the stock MGB 3.91:1 axle ratio? All Stock MGBs that thrive in the Mountains of Colorado or similar areas where the grades going up have shown Stock MGB engine are not up to the task of any higher peed gearing. For you guys, we First recommend the electric overdrive or a five speed. Secondarily, consider an engine conversion, or a properly built 1.8 engine with a Supercharger, or a very well built MGB engine with computer controlled fuel and spark to get the power up far enough to consider additional modifications.
Changing gear ratios on the stock MGB differential OR change out to a different rear axle altogether?
The costs for these gears in the 1968-80 MGB, seals, shims to tighten up the spider gears and other minor bits plus installation cost (Labour) is less than converting the MGB tube type axle to a narrowed GM, Ford or other rear axle once the 'dust settles'.
We highly recommend these installed by a proficient professional.
**When ready to install, we will help you select gear ratio choices. There are a lot of variables including vehicle weight, camshaft selection, fuel injection vs. carburettor, which gearbox you have (it is Critical that you know what specific gearbox ratios you have before you install that in your car- ask us Ahead!), driving style, flatlands of Iowa or the Mountains of Colorado and other issues.**