How is that? I thought the gm847 was longer duration higher lift and on a 110 LSA???

 

I am going to use 306 with 1.6 RR, my question is if i need to change the torque converter for a higer stall?????

 

My buddy had a stock headed 847 and I had a stock headed 306. My 306 surged pretty bad below 1800rpms and his drove just like his previous 305 and had absolutely no surge. He may have gotten his 847 on a 112 though. His car made tons of torque with that cam, while my 306 made all of its power at 4.5k+.

 

GM847 comes on a 112 LSA, unless you have it custom ground on a 110.

I'm the guy Kreinmc is talking about. I'm not sure as to why the GM847 drove better than the CC306 in his car because the GM847 actually has a little less aggressive lobe profile, very close the CC306 lobe profile. It may have something to do with the CC306s larger I/E split on a NA car. I also had 3.73s and Krein had 3.42s, which didn't help the CC306 at all. Can't go wrong with either cam.

 

Definatley, I fricken love this cam. I just wish I had more lope. Mine is on a 112 LSA. Are you sure it just wasn't the tune or maybe the injectors? I know the GM847 makes power at 3000+ and you can make power to 7200 rpm. THe 306 is similar but up to 6500 on stock heads and 6800-6900 on ported.

 

I think the 3.73s helped quite a bit and the tune may have had some effect, hard to say.

 

No clue, but looking at the lift and duration i'd say the 847 is much more aggressive. BTW, nice numbers for stock heads.

 

4* more intake duration and 2* less exhaust duration at .050" is hardly 'much more aggressive.' You also have to look at the advertised duration. The 847 has more advertised intake duration and less advertised exhaust duration, nearly proportional to their differences at .050". The advertised on the GM847 is 296/304 and the CC306 is 290/307. The ramp profiles are pretty similar.

Granted the GM847 has more lift, the ~ .030" lift difference isn't going to make the GM847 less driveable, and given the fact that the two cams have similar durations, it's safe to say the higher lift of the GM847 gives it a slightly more aggressive lobe profile and faster ramp rate, possibly making it a little more streetable than the cc306.

 

So with a T56, if I went with a CC306 would I need to step up the gears to 4.10 to avoid ******* because this cam generates power at a higher RPM?

 

I would go at least 3.73. I just got my 4.11's the other day and can't wait to get em in. That T56 6th gear ratio is .50 so I'm guessing 75 or so on highway is still going to be around 2300-2600rpm range.

 

if anything it would dog more....less power at the low end.. if you put a steeper gear in like a 4:10 then it makes the tires harder to turn. so less power more resistance would bog more... but if you rev it into the power band you have no trouble whatever gear you have.... not sure if i explained that well...

 

Comp cams says you need a higher stall but.......it has been run on a stock stall. I remember seeing a post about it last year so you can do a search if you'd like.My stall converter cost $425 brand new from West Coast Converters and it's done me very well so far.

 

actually you'd be going over 85 MPH at those rpm.

check it out at http://www.f-body.org/gears/

 

4.10s do NOT make the tires harder to turn. The 4.10s give you more mechanical advantage at the rear wheels allowing the car to accelerate quicker.

You have it backwards.

 

ok, so which is it???