I have never used an MSD in any car I've owned in the past 42 years. I've run the MP distributor with a stock box or a chrome box recurved and dialed in even in a 10 second street car.

On the car's that came with stock dual points I then used Pertronix conversions in them and all was well also.

I loved the Rev in nator in my old Satellite that came with electronic ignition because the Black box with a Chrysler Electronic sticker on it and an ECS letter transfer (green letters) on a Black Rev in nator coil is easy to hide and the system works great and has a rev limiter.

In the 68-70 cars you can easily mount any ECU to the heater box bracket under the dash and send the wiring out through your air grabber hole, put the proper distributor tag on the distributor to hid it somewhat too. Again use the proper black coil for the system and put the ECS dry transfer on it and most would never notice.

Lastly this time with my 71 Super Bee I bought a new distributor from Rich E. on E-bay along with his Rev 7000 ECU put a FBO limiter plate in it and springs and was very impressed with it's operation and quality not to mention the price.

https://www.ebay.com/itm/223426178580?

So I guess what I'm saying is you have many choices and there is always a way to camouflage them and also not have to drill holes in that beautiful firewall.

Ron