My 400 block has maybe 20K miles, its already 30 over, and the cylinder walls are still decent so I am only going to hone them (but, no torque plate).

I plan on no more than 400 HP and never more than 6000 rpm.

Given this situation, should I stay with cast iron rings?

Thanks!

Imho, just use a quick, dingle-berry hone job on her to make a good cross hatch pattern and some good moly rings and go..

Guy's, am I missing anything?

pdq67

I've also used dingle berry (flexhone, ballhone, rabbit turd hone) in this situation with good results. Just make sure to clean block thoroughly, and yes, use quality set of moly rings. Plain cast iron rings in my opinion have no place in any performance engine.

Maybe BillK can chime in here, but don't you have to use a different bore finish for moly rings than regular cast rings? Maybe have to use 2 different grit dingle berry hones?
I also think that in your application, a cast ring will be just fine. I've run cast rings an nearly everything I have ever built until the last few years and never had a problem with them on a under 6K rpm engine.