Looking for specific variable resistor

[LittleBlue79]

Okay so I'm working on a project and I need a set up that changes resistance based on a frequency input. I'm not really electronically inclined. As an example, this is going on a 1979 F150, and in my opinion, this will be more complicated than the engine management system.
The set up would be an led strip that changes brightness based on engine rpm. By tapping into the ignition coil at the 500-3000rpm range this engine uses you see a signal pulse at 33-200Hz. I think I need 150 ohms at 33Hz and 0ohms at 200 Hz in a linear style. This resistance would lower the voltage down to 9v effectively dimming the led. In my head anyway.
I don't know the terminology for this kind of stuff and am having a hard time researching what I need. Any help is greatly appreciated. I'll post pictures of the progress of the project here and if I ever get it finished a video of the final product.
I say thank you in advance and please be easy on me

 

[Bluejets]

LM2917 would possibly be a good starting point.
It's a frequency to voltage converter.
More than likely circuits out there you could adapt to suit your needs.

 

[duke37]

If you are wanting more brightness at higher engine speed, then I would suggest that each input pulse should put an output pulse into the leds. Some smoothing may be needed if the visual pulsing is objectionable.