How much quicker do you think my car would be with the 847 over my cc305? My nine inch ford rear is ready to go in and I have 4.10 gears on a spool, Im also going with a 3500 stall over my 2800. My current times are in my sig also is the gm 847 a gm performance part or is it made by someone else? Part #'s?

 

imo if you're want more than a 305, you should prolly get a diff cam then the 847.. i dont think its THAT much of an upper in comparison..