[Ronbo]

A lot of factors effect current draw. Number of cylinders plus compression ratio being the big factors.

Also since it's an inductive load, in-rush current will be quite high (400~600A in the case of a high compression, large displacement V8) untill the magnetic fields build to full capacity. Not to mention 80~90 lbs of metal (crank, rods, pistons). In the case of starters there are two current spikes; the field developement and the gear engagement.

Once everything is up and spinning the current will drop down quite a bit, gear reduction starters also run less in-rush but for a longer period of time. (ultimately it still takes the same power to do the job)

Unless you've done a terrible job running your battery cable to the engine, this is pretty much a fix for a non-existant problem. If you already have a cut-off switch, this is totally unneeded.

Ernie, Remember those awfull Olds diesel 350's? The car needed two batteries to crank the engine. My buddie's '68 Eldorado had a factory battery that looked like it was from a locomotive engine. (of course that 500 engine could probably pull a small train)