This guy has a great web page for making 850s go fast, you might try
it.
http://www.scuderiatopolino.com/Links/engine.htm
--- In geminatesfiatgarage@y..., whooahh007 wrote:
> I have two 850 Spiders. A '69 (not running yet)
> and a '72 running nicely but under powered. 52HP.
> Would like input on how to get more horsepower or info
> on another engine that will fit - without rebuilding
> the whole car! Thanks -will send pics soon.