http://www.v8archie.com/v8fiero.htm
Pretty much the best/most popular place to get the conversion parts, from
what I understand. Also do a search for "Fiero V8 conversion" on Yahoo or
Google & you'll find others.
I think the small-block chevy & Caddilac V8's are the most popular, & in
fact the caddy may not need the kit. Again do a search for "Caddilac V8 in
Fiero" or something similar (always pays to try several different search
phrases).
HTH,
~ Paul
aka "Tha Driver"

I had the 'V8 Archie" mod done to my 2M4.  Hard part was coughing up a
Getrag 5-speed for the conversion.  I used a Greenwood ZZ4 as the pp.  I've
been pretty happy with mine (lots of odd looks, and 'what's that' comments).
It really is fun putting mustangs in their place.  The only other mod that I
seriously considered was the supercharged 3800 by A.C.E. in Colorado.  Not a
v8, but an interesting sounding mod.  I heard a rumor that they (A.C.E.)
are not doing that anymore.  Anyway,  the V8 Archie swap is a good choice.
He sure knows that car!