well u take the cable size, if its run inside the cab it would be recommended to use a larger cable to compensate for insulation factors such as ambient temp etc etc, cable size being Cross sectional area (CSA).. if u were to use a 10mm2 CSA cable, u wouldnt get a lot of cranks before the cable starts to get hot. if u had a 70mm2 csa cable u would be able to get alot more cranks outta it.. in the end the starter motor is the biggest draw on the battery..

i agree reuby that in theory its better to run under the cab, its free to air and can dissipate heat.. so really if u like the look of a cable running under ure car go for it ;)

or just run through the cab and use a heavier gauge cablt to compensate. hehe as jordy would say " are you trying to compensate for something???" lol

it all comes down to the engineer, Oldschool has his running inside the cab in WA... thats a ca18det conversion