Question about inframe on 3406b 7fb 350hp cat engine

I believe that Cat performed that on a 89 T600 that I had, in 92 or so. Yours may have had it done already.

 

Maybe @wore out can help in what to look for.

Now that I think about it more, Cat may have pulled the head and drilled an additional hole in the block to improve coolant flow around #6, I'm not sure now. It was long ago and I'm getting old. I do remember that I took it in for a valve/bridge adjustment and they suggested to do it, with no charge whatsoever to me.

 

Scroll down to cylinder head passages. I think that should be it

 

Thanks @pushbroom !

 

The aftermarket heads I have used from Highway and heavy parts come pre drilled. I have not had any issues with the 4 or 5 I have installed. The new CAT heads do not come pre drilled and that hole has to be precise or you will get in the bolt bosses for rear lifting bracket. Also the new CAT heads are very clearly marked Maylaisia or how ever you say it. 3500 with core or 3 from H&H no core. What’s really better idk. Habits are habits and on my personal stuff I prefer CAT. However I do let the customer decide and it is his baby no matter the outcome lol

 

The square style is what’s on my 4MG.