Box Stock

Nr 272 cam

mike97760 said:
It would be worth asking the cam grinder directly about this using ratio rockers.
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I'd be careful using ratio rockers. The max lift on the cam (according to NR's site) is .275, so adding in the extra lift from the ratio's is going to push the valves pretty deep and faster than what the cam was designed to do.

I wouldn't say it's necessary to talk to "the cam grinder" about it, but more like make sure you check your clearances before starting it up. Also, I'd consider going with a heavier spring than the 26 lb NR recommends.

Different cam, but the result of adequate clearance but sticking with the recommended spring with ratio rockers...intake valve saying hello to the piston...didn't even make it past break in time before having to replace both the piston and valve.
 
So quick follow up for ya. I actually put this cam on a motor and took it for some hard laps and it performed pretty well. Seemed to have a little more oomph than the MOD2 (since that seems to be a relatively easy one for most people to compare to). Top end was comparable, but it did seem to produce power throughout better.

Don't have dyno readings for it so all I was able to go off of is my seat dyno, but when I immediately swapped motors to one with an otherwise equal everything but the cam (MOD2) and it seemed slower after the switch at lower and mid-range rpms...didn't feel tremendously different at the top...again, just seat dyno.

I used the exact same carb, exhaust and clutch for both just to keep it as identical and comparable as possible. Long story short, for what you're doing it's worth a go. It's not like it's an expensive swap...10 minutes and you're off and running...
 
Reign-Check said:
So quick follow up for ya. I actually put this cam on a motor and took it for some hard laps and it performed pretty well. Seemed to have a little more oomph than the MOD2 (since that seems to be a relatively easy one for most people to compare to). Top end was comparable, but it did seem to produce power throughout better.

Don't have dyno readings for it so all I was able to go off of is my seat dyno, but when I immediately swapped motors to one with an otherwise equal everything but the cam (MOD2) and it seemed slower after the switch at lower and mid-range rpms...didn't feel tremendously different at the top...again, just seat dyno.

I used the exact same carb, exhaust and clutch for both just to keep it as identical and comparable as possible. Long story short, for what you're doing it's worth a go. It's not like it's an expensive swap...10 minutes and you're off and running...
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Thanks for the info.

Have you compared it to something like the Dyno CM?
 
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