I currently have this setup...

355ci
-balanced rotating assembly
-ross forged pistons
-eagle Ibeam rods
-ARP main studs+head bolts
-cc305 cam
-stock heads port match comp ratio 11to1
-cloyes double roller timing chain
-cc1.6 RR,pushrods,springs,rocker studs
-mezeire HD electric water pump
-hooker LT coated headers
-clevitte H-series bearings
-taylor 10mm wires
-ngk tr55 plugs

This is all going through a stock M6 with Spec III clutch and 4.10 Richmond gears in the back (stock drive shaft).

I assume I'm pushing around anywhere from 350-400rwhp.

If I go from a cc305 to a cc306, how much of a gain will I be looking at without a tune? How much of a gain with a tune?

 

You will see more of a gain with a tune either way. From what I understand, the cc305 cam is more of an Auto Tranny Cam. The cc306 was designed for the Manual Tranny. You will give up a little driveability with the cc306, but you need a tune. If you install the 306 cam without a tune, you will have a little trouble. It will have an unsteady idle, and cam surge at low RPMs will be a pretty noticable. I have a great tune, and I still have some surge, and after about a month, the computer is still trying to figure out the idle we set. Either way, a tune is a definite necessity.

Hope this helps,
BIZ

 

Sorry, but I think you're at the lower end of that number, or lower, with the CC305.

 

A great tune will result in no cam surge with that cam. I run a large cam and have surge that is only noticeable at extremely low rpm in 6th gear. My car also learned the idle within 2 ignition cycles and idles where it should everytime now.

Sounds like you could benefit from a dyno tune from The Milkman

 

How much hp will I pick going from cc305 to cc306?

Should I even get a cc306? Is there another cam anyone would recommend? Custom grind?

 

depends on the setup.. I would guess 15 to 20rwhp? (anyone else?)

 

how about a GM 847?

 

I would get your heads ported if you want some more power. I would much rather have a milder cam and ported heads, then to have a huge cam and stock heads. Do a search people are putting down anywhere from 350-360 rwhp with the 847 and cc306. The cc305 on stock heads probably puts out about 325-335 rwhp. Do a SEARCH. I know Marcin has posted his dyno's of his cc306. I also know there was a thread on the 847 record hp #'s on stock heads.