Just as a bump to the thread, and to add on to those who might be searching about the 846, Like me... i just had a 1 on 1 dyno tune with Bryan Herter , the 96+ OBD2 programmer for pcmforless.com, for those of you who do not know...

and we got onto the subject of cams on stock head LT1's he said the 846 was probably the highest cam he'd go with on stock heads, 847 is Do-able but you wont get the full potential... this is comign from a guy who does this for a living... so i will trust his judgement