Pro Flo 4 Timing

I played on my setup with the adjustable MSD cap last year, my baseline situation was that the car ran well in general, only in some cases at full throttle and high RPM y noticed some instant hesitation and backfire. After playing withe the timing in the app and so on I could not get rid of it so I got the cap and installed it.

Installation was a breeze, adjustment is easy as well. Nobody had a reference on hoy many degrees they tuned their cap to, base on pictures and visually I set it to 5 degrees advanced. The car felt good at low RPM, but then at high RPM the hesitation worsened.

I then retarded it 5 degrees, thinking I may have done the change to the incorrect side. It just took a short drive to realize this did not wor at all. So I backed it up to zero, as it was initially.

By looking at all the parameters in the full digital view I noticed there was always some amount of vacuum, regardles of full throttel driving, etc, it never got to zero, so it was always adding some advance since I had 5 degrees of vacuum advance set. There are some videos and posts where this issue is explained as well, it seems an incorrect reading from the sensor at the application, just like the voltage value.

I went back to play with the parameters in the edelbrock application, at the end I was able to solve this eventual issue with parameters modifications only. I ended up with 11 degrees idle spark (I live at 7200 ft above sea level and my engine has 12.5:1 compression), start advance at 1150 (Hughes cam shakes the car too much at lower RPM :), a total spark advance of 29 degres and full advance at 2000 RPM (I have a 2.73 rear end gear ratio, so you can drive it still even with full advance at low 2k). With this the car pulls hard and there is no hestitation at any RPM, hopefully will test it at the dyno soon.

So, In summary in my case the adjustable cap did not make that much of a difference for the problem I had, it could be adjusted with the application settings.

Take care,