Mile Hi GN
Member
- Joined
- May 23, 2001
- Messages
- 184
I asked my brother (Ford GT / Ford GT 500 guy) to comment on my new camshaft choice. Upgrading from the "club" 200 FT to the Comps 206 roller. I found his comments informative - you may also:
The .070 lift increase with stock ratio rockers is a large increase in lift. Not surprising, though, given the change from flat tappet to roller lifters. Flat tappet to flat tappet lift changes in this range are not as dramatic due to their slower ramp speeds. The Comp Cams spec card says "not campatible with stock spings" (no surprises), but I am assuming you have the springs worked out. You will likely need different springs to handle the higher lift and control the heavier lifters. Rocker/pushrod geometry will also need to be verified. I am surprised at the tight 107 LCA (Lobe Center Angle) of the Lunati cam. This would allow max overlap on the mild specs of this cam. The LCA of the new cam is 110, which is not a wide LCA by any means. Some naturally aspirated cams have LCAs as wide as 115 degrees, though this is less critical on EFI engines. "Works with stock computer" generally means a cam that makes good idle vacuum, which especially helps cars with MAP sensors (speed density cars). Overlap (LCA angle) tends to affect idle vacuum. Generally speaking, "tight" LCAs (less than 110) tend to be peakier power delivery, "wide" LCAs tend to be broader power delivery, if a bit down on max power. This is a change in the correct direction for a street car.
800-5200 RPM is right where we live on the street, and Comp Cams does a good job of describing their cams' operating ranges. Considering your engine does not want to rev past 5300-5500, I would say this is an excellent choice, and will make better power everywhere when under boost. In my estimation, this cam would likely make a better N/A cam than the Lunati, which means your engine may actually make slightly better torque in the pre-boosted ranges of its RPM band. Time will bear this out, but I will bet your car will make slightly better power down low with this cam. You will be able to tell this change (for better or worse) instantly when you drive your car.
Of course, this change should have been made when the Admiral boys had the heads and intake off of your car! They were literally at the house next door to where the cam lives. Now, they get to go back right into the same neighborhood. At least they know where they're going. However, it did let you make one change at a time, which is considered the safest approach.
I think its all good, and the specs look like a nice, conservative change as I would prescribe.
The .070 lift increase with stock ratio rockers is a large increase in lift. Not surprising, though, given the change from flat tappet to roller lifters. Flat tappet to flat tappet lift changes in this range are not as dramatic due to their slower ramp speeds. The Comp Cams spec card says "not campatible with stock spings" (no surprises), but I am assuming you have the springs worked out. You will likely need different springs to handle the higher lift and control the heavier lifters. Rocker/pushrod geometry will also need to be verified. I am surprised at the tight 107 LCA (Lobe Center Angle) of the Lunati cam. This would allow max overlap on the mild specs of this cam. The LCA of the new cam is 110, which is not a wide LCA by any means. Some naturally aspirated cams have LCAs as wide as 115 degrees, though this is less critical on EFI engines. "Works with stock computer" generally means a cam that makes good idle vacuum, which especially helps cars with MAP sensors (speed density cars). Overlap (LCA angle) tends to affect idle vacuum. Generally speaking, "tight" LCAs (less than 110) tend to be peakier power delivery, "wide" LCAs tend to be broader power delivery, if a bit down on max power. This is a change in the correct direction for a street car.
800-5200 RPM is right where we live on the street, and Comp Cams does a good job of describing their cams' operating ranges. Considering your engine does not want to rev past 5300-5500, I would say this is an excellent choice, and will make better power everywhere when under boost. In my estimation, this cam would likely make a better N/A cam than the Lunati, which means your engine may actually make slightly better torque in the pre-boosted ranges of its RPM band. Time will bear this out, but I will bet your car will make slightly better power down low with this cam. You will be able to tell this change (for better or worse) instantly when you drive your car.
Of course, this change should have been made when the Admiral boys had the heads and intake off of your car! They were literally at the house next door to where the cam lives. Now, they get to go back right into the same neighborhood. At least they know where they're going. However, it did let you make one change at a time, which is considered the safest approach.
I think its all good, and the specs look like a nice, conservative change as I would prescribe.
