cranking rpms for starting?

[GREASE FIRE]

i recently had an electrical problem with my 6.2 that made it hard to start - basically one of the batteries was low and sometimes it would not start until i charged it up even though it would crank and crank.

Now, i know the batteries are brand new on my 7.3 but it takes quite a bit of cranking to start and it seems to turn over kind of slow when cranking, so i am wondering if something is preventing it from getting the kind of rmps it needs for an easy start. I know the starter is also new but perhaps the cables are getting worn out. Since i have a tachometer i was wondering if i could use that so see how fast the engine turns when cranking, and that would tell me if i have a problem in that area.
Can anyone tell me what rpm's i should be seeing when cranking?
thanks,
paul

 

[LCAM-01XA]

I know mine hits 500 rpms, according to the tach, I think 400 was the minimum. After the new 3-0 cables Jake's 6.9 with a new starter hits 700 according to the tach, but dunno how accurate that is.

 

[smoking89IDI]

Don't forget about the starter relay, if it is old it is probably burned inside and you will loose amps there as well, even just cleaning and re-tightening all the cables can make a HUGE difference.