Good Day and Howdy
 

Joining your group.
this machine was in commuter service getting @ 27 MPG 330 miles a week .

now no commuter service.

for the last period of time it has been in refit for top coat and interior ,

FE Trials start in March

any suggestions for modifications ?

for a 1979 MGB
see the garage for current status

thanks

Welcome! You might want to start by lowering the car. MGB's prior to 1975 sat considerably lower than post-75 cars; they raised them due to federal headlight height and bumper standards. I'm sure a search of enthusiast sites would find a wealth of information on how to drop the car back down. It would also improve the handling, which on MGB's is very good to begin with; the roadsters have 50-50 weight distribution with the vast majority of that weight located between the axles.

lowering by 1 " is very possible with a kit, 84$ for the rear and new spring up front 60$ ,, + labor

is it possible to predict the % increase in FE resultant from 1 " lowering so that i might calculate cost/benefit ratio

What about overdrive? My 73 Triumph had it. It was a separate unit that mounted on the rear of the transmission. As I recall it was good for a 500 rpm drop and I could use it as low a 45 mph.

5 speed od conversions are available @ $3500

OD units available @ $1000 new , serviceable used units at abt 600$ when one can be sourced + i think it requires change out of gearbox innards.

they will increase FE by est. 20% . from @ 30MPG to @ 35 or so. using current $3/gallon if i calculate correctly results in 1.7 cents per mile cost saving or less than .0066 gallon/mile . . resulting in break even mileage of about 59000 miles for the new unit and 35000 miles for the used unit ..

i would like an OD . its on my list

TY

The MGB OD is a separate unit, a set of sun gears stuck between the tailshaft and the driveshaft. IIRC the gearbox itself has an entirely different (cast aluminum) transmission casing. (The one-piece cast aluminum case included the bell housing too - B's were pretty cool cars, from an engineering standpoint.) The OD works in 3rd and 4th gears with factory wiring, giving you 6 forward speeds total. You can easily disable the 3-4 limitation and get 8 speeds, but I'm not sure that would be of much value.