Anything is possible with the correct tooling.
These reproduction crossrams are made In Mich.
Correct GM Casting #'s,Winters snowflake,etc.
http://cgi.ebay.com/ebaymotors/1968-...QQcmdZViewItem
69" Z28 302's LT1 350 came in 4 bolt main only
Some castings are 3932386
Machine shops take a Two bolt 327 3932386 Install 4 bolt caps/Align hone mains it's already date code correct as they were produced in 68-69 and Installed in Impalas and such in two bolt main version only.