A friend of mine has a 1996 LT1 M6 Firebird WS6. Gorgeous and runs damn good aswell. He has the LT1 hot cam in it now I think the lift is 525 or 530 or something. He was told not to go over 545Lift with the cam because he has stock heads and bottom end with a LT4 intake. He runs nitrous but he wants it to run good NA and react very nicely to the nitrous aswell 150shot. I am pretty sure he is NOT wanting to flycut his pistons and he has 1.6 roller rockers. Any info would be greatly appreciated.

 

The stock LT1 heads don't flow much over 545 lift (w/ 1.6s). Its not really worth it to get a cam that has lift that high if your heads arent going to flow it.

BTW He has a LT4 intake with LT1 heads? How does that work?

 

KC formula is right, it's probably not worth it to go that far.

There is no one answer on the lift because it depend on the exact lobe ramp, duration, and advance of the cam. In other words it will vary, also depends if your talking 1.5, 1.52, 1.6 OR the actual cam lift.

There are some people running the GM 847 on otherwise stock motors

12370847
Hydraulic roller design
NA

NA
I:234
I:539"
E:242
E:558"


Zero/Zero
112
which is .575 and .595" on 1.6 ratio!

-brent

 

What is the max lift the stock springs are good for btw??

Jeff D.

 

Stock lift, hahhaa

Just going to 1.6RR on the stock camshaft has caused people coil bind on the exhaust side.

 

From what I understand its a matter of different gaskets to make the LT4 intake fit and there is something else but i forget.


I'm just talking the maximum "CAM" lift with 1.6 roller rockers with the stock LT1 heads. He is buying upgraded springs to put on with the new cam cause the springs he had put on with the hotcam wont take any larger and they are due anyways. So are we saying 545 lift cam is the max he can or should go???

 

i wouldnt really worry about max lift possible. you'll start smashing (stock) lifters way before you get there. its somewhere around .600" maybe slightly more (dont remember exactly) but it does depend on where the event timing is just how much you can run. not going to see a lot of gains on stock heads with more lift just more abuse on the springs and other valvetrain parts.

Edit: i just noticed you said cam lift. i'd worry about valve lift more than i would at the cam. the lift at the cam determines the lift at the valve. if you have 1.6 rockers its (cam lift * 1.6) = valve lift. honestly there arent really many grinds out there that will hit max lift possible.

 

Im running the CC306 with stock heads, some have gone bigger and it puts out the power nicely.

I did the calcs on my cell phone so I dont know if they are accurate:

With the 1.6 RR's.
.544 on the intake side
.576 on exhaust

 

I wouldnt go any bigger than the cc306. I had a cc306 on stock heads and I thought it was to big.
Scott

 

How about the G.M. 12370846 cam? Specs are:

Lift w/ 1.6 RR

I: .543
E: .563

Duration at .50

I: 222
E: 230

112 LCA

Sounds like it might be a good middle of the road cam to me...
Just my .02

 

A cam for stock heads is not all about the lift. It's about everything else.

The big thing you have to do is upgrade the springs, there are only a certain number of springs that will fit on a stock head that will do what you want.

On top of that it's the goals you have for the car.
What kind of idle do you want?
What is the rest of the combo? Gears? Tranny? Bolt Ons?

BTW my professional opinion is that the CC306 is too big for stock heads, on a stock bottom end.

Bret

 

IM running the 847, 575/595 on stock heads. Not having too many issues with lack of power, just no traction, lol

 

Well as I said he is going to change springs aswell with the next cam. What springs would be good for the stock head and handle 545lift for example. Not looking to modify the heads just for the springs etc. So the CC306 cam is too big by most opinions. Its getting late in the game to choose a cam. Any help is greatly appreciated.

A break down of the car.

LT4intake, stock heads, Hooker LT's 4in mufflex Ypipe cut out, 3.73s, NX wet kit, ram air, basic bolt on car that had/has a Hot cam in it now. Is there atleast a cam out there that he'll see some nice gains over the hotcam???NA and with Nitrous>?

 

on the juice 114lsa would be benefical. The 227-233 on 112 or 114, or the 230-236 on 112 or 114 would make more power than the hotcam. They also would rev higher.

 

I have it in my daily-driven Impala SS. I even have a T-56 with 3.08s in the back and it is still not too bad. I would say this cam would be very nice in a lighter car. I do not know if this would be a good nitrous cam. I think you want more lobe separation and less overlap.

Matt

EDIT: I am also running stock aluminum heads