CC306 or Gm847?
 

I've been contemplating purchasing a new cam for my car. I currently have a CC306 cam that I bought used, but it has been through 2 motors & 2 spun bearings so I'm feeling a little iffy about its condition. Is it possible to get that looked at by Comp Cams? I figured it was safe to buy a used hydraulic cam but I don't know all of its history or where else its been.

If I were to have to go ahead and purchase a new cam I wanted to see which cam would net me the most use able power for an off the shelf grind cam.

CC306 = 230/244 112LSA

GM847 = 234/242 112LSA


The cam would be going into a new short-block with GM bearings & new gm oil pump with a warranty.

The 847 is a bigger cam and makes more power higher in the RPM range. Although they look close the 847 difference is the intake lift.. If you look at the cam cards, the 306 cam is listed as 5800 RPMs, the 847 at 6800 RPMs.

I recently did an LE stage 2 heads with a 847 ( 1.6 rockers )on a stock bottom end ( normal other stuff, LT headers, 3400 stall, MadZ28 tune ). It chassis dyno'd 380 HP and went 11.2 @ 110MPH.

Also installed an 847 on stock heads/bottom ( using behives and 1.5 rockers ) and made 340HP ( Mac shorty heads, stock stall MadZ28 tune).

Since both are stock bottom ends the shift was set at 6400.

The 847 W/ 1.6 rockers is 595 lift. That pushing the limits of the beehive springs which is why we opt'd for the 1.5 rockers on the stock heads. I know people do it, but I perfer not to push that hard!

I'm just worried about spinning bearings. I'm currently running Comp Magnum 1.52RR, Comp 977 spring, Comp Ti +.050 retainers/seats/locks one ARP 7/16 studs.

I'm starting to wonder if these cams are to big for "stock-ish" bottom ends since it seems to be a crap shoot on what motors do what. Unfortunately thats the way things go with modifying engines.

just be careful with your break in procedure and you should be fine.

running the mods in my sig and making 380rwhp, 370 rwtq stock. HP peaks at 5900rpm so I don't have to spin it high and this is on the stock bottom end. Pretty happy with the cam but do not have experience with the 847.

-Brian