A lot of peeps have been considering swapping their tired 305 or 350 with a GMPP crate zz4. This site offers a good deal of information detailing just that. A zz4 swap. Good photos and detail of steps, including dyno runs. Also there are bolt on upgrades, LT4 hotcam, 1.6 RR, AFR 190cc heads, etc. I found it helpful, since I'm seriously considering the swap myself. I have heard that GMHP or High tech did a work up on a zz4, i'll look for that as well.
Please post any other supportive sites for this swap.
Thanks!

http://www.eecis.udel.edu/~davis/z28/winter01/dyno/
Here is a carb version of modifying the ZZ4. Write up and coverage by GM High Performance mag
http://www.chevyhiperformance.com/te...ild/index.html