I bought this cam locally used a few years ago and was told it was a GM847. I'm looking at installing it but want to be sure I know what I have. It doesn't seem to have GM847 part numbers, here is what it does have for numbers.

The part number stamped onto the cam shaft behind the fuel lobe is: 109516 03G1A

On the end face of the camshaft by the dowel pin these number are etched:
HR296 - 2S12IG and right below it is 10-35-03

I measured the lobes and found lift to be:

.359 which would be .5385 on a 1.5RR and .5744 on a 1.6RR

.373 which would be .5595 on a 1.5RR and .5968 on a 1.6RR

If anyone could help me out I would much appreciate it!

 

part #HR-276-2S-12 IG (hydrualic roller)

specs are: 214/222 .488/.509 112 LSA

 

Crane- 109841

http://www.jegs.com/i/Crane/270/109841/10002/-1

It's Crane's version of the GM847.

 

Thanks for the quick help guys! Now my next question is there is only one small nick (about .032 X .032) on one of the cam journals. I can hardly catch it with my finger nail, I don't know if this would casue an issue or not. The rest of the cam looks great.

I'm thinking this cam may need more RPM than my stock 93K bottom end is willing to take for long. I'm not wanting to spin more than about 6300. My CC305 peaks around 6050RPM right now.

 

The nick needs to be smoothed out and chamfered. If it catches on your fingernail it may have enough of a rise to really do some bearing damage. I had this same cam and for me it peaked right around 6200rpm.

 

Thanks for the info. Were you using this cam on stock head?

I am running some mildly ported heads from a long time ago on the car. The guy who ported them had them flowed and were just above the stock LT4 head flow. I know that doesn't say much about the heads potential or flow but thats all I was given for info.

 

I was using LPE LT4 CNC ported heads and LT4 port matched intake.

 

Crane Cams ground the GM847 cam for GM. I'm guessing GM just relabeled it with part number GM 12370847.

 

Thanks guys. I think I may install it this winter, it shouldn't cost much as all I should have to change are the valve springs, retainers and locks and gaskets.

SS RRR, what kind of power did you make with this cam?

 

Do you already have hardened pushrods?
I would add ARP rocker arm studs to the list.
I usually recommend NSA rockers and guideplates as well. You'll probably want 1.52 ratio rocker arms with that cam.

 

399.9rwhp and 360 torque. Never got it to run worth a crap at the track though. Wrong gears. Should've had 4.10's and had 3.73's. Story of my life.

 

Ya, I've already got all the supporting items you mentioned from when I installed the CC305 that is currently in the car. I do have 1.6 rockers though and thought about going to 1.5s with this cam. Still not sure what I'm going to do, but I have a few months before 09's driving season is over to decide. Thanks guys

 

With 1.6 rr's the lift of the cam will be ~.575/.595. Taking into account a ~.025 buffer, you need springs good to ~.620 lift.

 

Ya, the lift with the 1.6 rockers is a little higher than I planed on going. At what point on the stock short block does piston to valve clearance become an issue due to lift?

 

Not sure, but I don't thing .620 lift would be an issue.

 

duration is more important to ptv clearance than lift #'s

 

You might want to check to make sure you will have enough spring for that cam if you decide to use it. Also, don't forget there's a difference between peak HP and actual shift points for the best performance.

 

I was planning on new valve springs, retainers and locks if I do install this cam. I agree with you on the power under the curve, I really don't want a combo that just peaks quickly.

What I really want is to do a AI head/cam setup but my stock short block has been through hell (95K miles) and don't want to spend a bunch on the top end only to have the bottom crap out. I would rather just hold off on the AI setup until I am ready to do the entire engine.

I'm just looking at the GM847 cam because I got it cheap and I have the needed gaskets already. Thanks for all the info.

 

95k miles is nothing for a well maintained engine. I would perform a compression test. If everything checks out and your oil pressure is strong, I wouldn't hesitate to do an Ai heads/cam install.