Well, I have to be honest and say I don't know how to read that spec sheet.
First, here is the spec for the factory "068" cam, the SAE standards used to provide the cam specs on factory cams was measured at .006" off the seat:
Pontiac "068" cam
LSA - 116
Intake Centerline - 113
Valve Overlap - 63
Intake Opens - 31 BTDC
Intake Closes - 77 ABDC
Exhaust Opens - 90 BBDC
Exhaust Closes - 32 ATDC
Intake Duration - 288
Exhaust Duration - 302
Valve lift - .406"
Here is a further explanation on cam spec by the guy who specs/grinds them:
"Re: Cam Duration: Advertised vs. .050
I always hate it when this bag of snakes gets dumped on the floor......
There is one place to rate hydraulic cams according to the SAE, the Society of Automotive Engineers, and that is at .004" ramp height. That equates to .006" valve movement with a 1.5:1 rocker, .007" with a 1.7:1. This movement allows for valve train compression, etc, and supposedly gives a .001" lift off the seat.
Companies do not all use this number, because customers are always looking for that shorter and shorter seat timing coupled with a lot of lift. But valve trains MUST follow the Laws of Physics, and there are limits to how fast a valve can be opened.
Here are some duration numbers and how they can change based on how the cam manufacturer lists their numbers:
UltraDyne Cam 272 @.0045", 266 @.006", 217 @.050", 127 @.200", .454" lift -1.5 rockers
VooDoo Cam 256 @.00?", 213 @.050", 125 @.200", .454" valve lift with 1.5
CCC 267 @.004", 259 @.006", 213 @.050", 126.4 @.200", .454" valve lift with 1.5
CCC 273 @.004", 265 @.006", 219 @.050", 132 @.200", .470" valve lift with 1.5 "
I have a Dyno 2000 engine analyzer program I like to play with and just for chuckles, made an attempt to input the numbers on your cam card. Using 10.5 compression, 750 carb, dual plane intake, big valves, good flowing exhaust. My input numbers are seat-to-seat. I cannot input any of the negative numbers, so I used the next closest whole numbers, ie "0" for the Intake and "1" for the exhaust. This also altered the LSA & Intake Centerlines slightly, but not much. What I got out of the program was miserable - no power but it had torque. Peak HP was 285 @4,000 RPM and all done at 4,500 RPM's. Peak TQ was 495 @2000 RPM's and down hill fast from there. Almost has the feel of a 455 - big TQ, low HP, but it'll be good at the lower/cruising speeds. Do you tow a 38 foot house camper? LOL
But the good news was this. I used some of those numbers to come up with a killer cam :yesnod: on my engine program (which is not 100% like many of the highly evolved dyno programs). Cam specs on the program are again set to seat-to-seat values.
LSA - 112.2
Intake Centerline - 107.2
Valve Overlap - 43.6
Intake Duration - 264
Exhaust Duration - 272
Intake lift - .443"
Exhaust lift - .442"
Intake Opens - 24.8 BTDC
Intake Closes - 59.2 ABDC
Exhaust Opens - 73.2 BBDC
Exhaust Closes - 18.8 ATDC
The RESULTS:
Peak HP - 417 @5,000 RPM's
Peak TQ - 487 @3,500 RPM's
The graph showed a nice steady power & torque line, so it was a good looking cam. In this spec, it is a big increase in HP over the original inputs, and pretty darn close on TQ at a higher RPM value.
So I am not saying your cam is a bad spec, as I honestly am not sure how to read it or how it converts to what style of cam specs I am more familiar with. So my inputs into the Dyno2000 program could be way off or, you are going to have a torque monster at low RPM's and not the HP a Pontiac engine has the potential for.
So do keep us posted on the results once you get it installed and up and running. It should be interesting and would be a great hands on comparison with the Dyno2000 results.
:thumbsup: