40° Pressure Angle, 36 Teeth 4.285 Pressure Angle, Please help

I need to create data for special gear for my customer, this manufacturer no longer make. I am trying to make a model with formulas to accomplish this. The only information that I know is the Pitch Dia, Number of teeth and the pressure angle. I think the pressure angle of 40° is what might be causing the problem. Is this because many machine formulas are based on approximations and this pressure angle is so far from normal the formulas do not work? My Base Circle seems way too small. If you cannot help me I understand.
Thanks in Advance

In my four decades of experience, I have only heard of two pressure angles for gear teeth, 14.5 deg and 20 deg. That's all.

There are spline deigns with involute teeth up to 45 degrees but these have "stub teeth". You may have some similar modification to the standard tooth profile that we cannot discern.

Juvinall, in 'Fundamentals of Machine Design', 1983, Wiley & Sons, states that 25 degrees is also a U.S. standard, (p.464), but I have only seen one set with that large pressure angle.

It's not uncommon to just specify all of the parameters of a gear with respect to the AGMA standard...

Modeling a gear is serious work - like the I did with the following webpages.

[url]https://www.engineersedge.com/gearanimator/[/url]

[url]https://www.engineersedge.com/calculators/spur_gear_calculator_and_generator_15506.htm[/url]