In a previous post you were talking about using the 440 Source aluminum caps but mentioned the iron ones as first choice. I bought a set many years ago at a swapmeet and never used them, yet. Just one question they are all the same, no thrust bearing register, did I screwed or is that the way they came?

It depends on which brand they are, more than likely yours are not the
Mopar brand. They came with the center cap machine
Milidon, KB and a lot of others don't come with them
Do you have a good machine shop to do the work for you?
Hopefully so

[img]caps[/img] Thanks they were cheap so I took a chance. they were in a Mopar box but buying used don't mean nothing.

Mopar had many different vendors on many of the same part #s over the years that weren't exactly identical to each other
Maybe yours where from KB in the older Mopar boxes
I bought 5 or 6 sets of the Mopar brand starting in around 1999-2001, all of them had the thrust surface machined, the last set I bought in around 2009 was from Milidon and they weren't machined
I'm using 440 Source brand aluminum main caps now, they fit well, according to the machine shop I use, and work well so far
I shouldn't be afraid of using steel main caps, especially on a RB block, but I am

What are the concerns with steel main caps? I have a set I was planning on using on a RB project. Just rounding up parts now.

My concerns on using steel main caps on a cast grey iron block is I'm worried about the steel caps causing the main webbing to break sooner than the stock cast iron caps will due to dissimilar metals harmonic factors Maybe one of the brighter guys on here that know a lot more than me on this will chime in for better information input
The after market aluminum and ductile iron caps don't have a history of doing that
I've assembled several KB aluminum blocks, they came with steel main caps from KB so I know they will work fine on a aluminum block
Now the real question for you is "Are you feeling lucky"
I'm not

In my opinion, if it's a 400 block I don't see the problem with billet steel caps, which is the route I took. I would not do that on a 440.
I think 1k to align hone, and align bore is a lot of coin to put a cast cap back in.

Of the two shops I use they pefer the caps that are uncut and cut the thrust area themselves as they feel its more accurate of a job.

But ive had mopar caps from the box, same PN with some cut, some were not.