Is it a eazyrun 5.5turn motor with cooling ribs around it?
If so it's a 480 sized motor instead of a 540 size. This means you can't compare it or ask anyone advice on it either because noone runs that size motor. Your MadRat and your B4 have the same internal reduction, so if you already know how to run it in the madrat gear it the same for your B4.
Otherwise you could always do what other people do and time your runs. If your speedo is boiling after 4 minutes you are too long and if it reaches top speed immediately it's too short.
By the way my BMW read differential has a final drive ratio of 4 in 1 hot exhaust. Do I have to squish a Banana on my left front tyre to make my fuel tank into a pram? What happens when I unscrew my bellybutton.
Wibble wibble...
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