Rod resizing, how important?

[340727Dart]

I've got a set of 340 rods that I am going to put ARP bolts into.
Is it imperative to have the big ends resized?
Mainly, I'm a bit confused by the term "resizing."
The way it's been explained to me before is that the mating surfaces of the rod and cap are trimmed ever so slightly to get them parallel.
That little bit of trimming changes the diameter of the big end, and the diameter then needs to be honed back to size.
Or, can I just change the bolts, slap in new bearings and go?
Thanks.

[Fast One]

Resizing is a very good idea, I'm doing a 318 at the moment & the rods big ends were about 0.002 out of round, only a streeter but I'll still get the service done.

[phoenix]

Get the rods resized if changing the rod bolts! It is very important due to the "relocation" of the cap to rod alignment after new bolts(ARP) are installed. Remember that rods are sized to the "ten-thousandth", so don't fool around or it could cost you lots more later! Also, don't go for the cheapy crap job at a generic shop, go to a blueprint style machine shop. The way to tell the difference is a "blueprint" shop will ask for your crank and bearings to be supplied so as while they're sizing the rods they can "set" the bearing clearance. At the very least they should ask you "what size you want 'em resized to". For example "high" side, "low side" or "midsize".

What's the application intended for the 318? What R.P.M.?
What grade (wt.) of oil to be used?