Folks

I need some help working out this cam specs sheet for my motor.

The cam is from JTS Performance with the following specs

Profile - 104CB
Actuation - Flat Tappet
R/Ratio - In 1.5 Ex 1.5

Cam Lift
In - 282
Ex - 281

Duration Adv.
In - 274
Ex - 271

Duration @ 050
In - 212
Ex - 212

Valve Clr
In - 0.013
Ex - 0.013

Valve Lift
In - 0.4092
Ex - 0.4077

Cam Lift tdc
In - 044
Ex - 038

Phase <)
In - 110

Timing Adv
Open
Ex - 66.5
In - 28

Close
Ex - 24.5
In - 66.5

52 Deg Over-lap


Timing @50
Open
Ex - 37
In - -2.5
Close
Ex - -5.5
In - 35

-8 Deg Overlap

Trying to get information from most performance shops is hard at the best of times, but once you mention datsun, or you dont want to part with your cash right now, they become very unhelpful

I rang Neil and got some good advice and called Jeff Taylor from JTS who built the engine, and got conflicting results.

JTS say dont bother, but everyone else says they are great. After much deliberation and thought, I plan to get some, but now i just have to decide the ratio to order. They come in 1.55 and 1.65 with standard bieng 1.44 I believe.

I used an online calculator hererocker calc

to see if what I can do is possilbe and it seems that its not going to happen if i am reading my cam sheet right.

The valve clr or clearence is the distance from the valve at max lift to the piston which is 0.013

according to the calculator, if i change to 1.55, I will gain 0.0138 lift.
With only 0.0130 valve clearence my valves will hit the pistons.

Is my intepertation correct??