Higher Lift Cam

[croucher]

I was at this website: www.3800performance.com and I noticed on there comp cams, there are two.

Comp Cams Xtreme Energy L36 Cam 1
and
Comp Cams Xtreme Energy L36 Cam 2

I figured that they were the same but then i looked at the ratios.

Cam1
Xtreme Energy L36 Cam 1 Specs:
- Duration at .050 = 191 degree intake/201 degree exhaust
- Intake Lift = .300 (.480 lift with stock 1.6:1 rocker ratio)
- Exhaust Lift = .312 (.496 lift with stock 1.6:1 rocker ratio)
- Lobe Separation = 110.0

Cam2
Xtreme Energy L36 Cam 2 Specs:
- Duration at .050 = 201 degree intake/205 degree exhaust
- Intake Lift = .312 (.496 lift with stock 1.6:1 rocker ratio)
- Exhaust Lift = .300 (.480 lift with stock 1.6:1 rocker ratio)
- Lobe Separation = 112.0

Which ones best for my 99' 3.8 L Firebird? I have no idea which one to choose? If in the future i put one on.

[croucher]

Shoot does anyone know what these ratio's mean? I have no idea.

[Tim81ta]

Alright here's what you need to look at. LDA Lobe displacement angle, it's the difference in degrees from center line to center line of each pair of intake/exhaust valves. The lower the number, the narrower the power band, "lobing", the higher the wider the more drivable.

Two, your durations goes along with your compress ratio. If your taking the "stock" cam out and replacing it with a "big" cam, you should look at how big your duration is going to change. As a rule, I wouldn't put in a cam with more than 30 degrees more duration with out changing the compress ratio.

I would look at what specs you have right now, in fact post them, then we can get a better look at what your working with.