Q45 motor. Not too hard to come by. They can make crazy power, when boosted.
http://cgi.ebay.com/ebaymotors/89-92-Infiniti-Q45-4-5L-V8-VH45DE-Engine_W0QQitemZ300075306022QQihZ020QQcategoryZ33615QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
there’s one for 750.
It’s not done yet though…