I am working on my 408 this weekend and came up with a few questions. First, what clearance is acceptable for main bearings and journal bearings? I have .0015 on the mains now, I think is OK but I am not sure. I have not tried the rods yet, but I should get them on tomorrow.
Second, does anyone have the part number for the ICS Titan head gasket off-hand? I found multiple part numbers and wanted to double check to make sure I order the right set.
The Caddilac lifters should be here soon and the WCCH Edelbrock 245s and VicJr will be going on soon .
Thanks!

 

That is a little on the tight side for me. It is within a runable spec but for a performance engine i'd stray to .0025-.0035 on the mains and .002-.003 on the rods. Putting them on the higher end generally requires a little heavier oil like a 40w but gives exra protection when deflection occurs at high engine loads IMO.

 

everyone I talk to likes more clearance than that for a performance oriented engine

 

Thank you for the help. I am going to check the rods out today, I may need to order .001 over bearings. I don't want to have any worries in the back of my mind once this is assembled and running.

 

The last couple I've built I had to go with .001 over mains.

 

I have a set of .054 titans brand new if you are interested that I ended up not using in my rebuild.

 

I will 2nd that, my 1st 408 had loose tolerances (performance) but were still in spec and i had 15-20lbs of oil pressure at idle with 20w50 royal purple racing oil.

 

That's within factory spec, I'd stick with that.