Here is a link to a FAQ that has a good conversion process.
http://www.ucalgary.ca/~csimpson/Tech/RConvert.html
This one has lots of info and claims external regulators burn up HEI modules.
http://my.inil.com/~dlbrown/ofign.htm
And this one is probably the best:
http://www.442.com/oldsfaq/ofall.htm...r%20Conversion
------------------
70 GMC 3/4 ton Sierra Grande 402/TH400
72 Jimmy 4WD 4spd 4" & 35's
64 Corvette Coupe
68 Camaro 'vert TPI & TH700
69 Z/28 355 12.6's @110
72 Datsun 240Z-ol' reliable