I built a 408, with a 6.0 block, running a callies 4 inch crank and callies rods. I want to use my ls1 oil pan and windage tray. Can anyone tell me how much i need to shim the windage tray to clear and will the tray built into the pan need modification also. Thanks in advance for the help.

 

Here's an option
http://www.slponline.com/view_product_site.asp?P=12510

But all I did was go to Home Depot and bout lots of metal washers and added til the crank stopped hitting the tray. No problems til now

 

The SLP spacers are a good option, I just turn out a box of my own on the lathe - they're ~ .200" thick. Sometimes I just add a little dent to the tray as well to clear the tight spot as the rod comes around. Look for .050" clearance.

 

.125 and it will clear you can use ARP 7/16 head washers