Mercury uses the 811637T superseded to 77-8M6008208 ignition module on EST Distributors for V6 & V8 EFI engines, it seems to be a GM D1965A or 10482830 module. Do they use this module for both EFI and Carb applications? Am I correct saying the ECM controls the timing advance curve and not the modules listed?

The module is used on EFI and carb engines. The module provides spark to get the engine running, and once the ECM sees the RPM signal from the module, it takes over and provides timing. Without the ECM, the module controls all advance functions. It throws a lot of timing early so it works well for taming idle with bigger cams, etc.

If you need one... finding a workable D1965A can be tough. I bought distributors for the blower motors in the Cigarette and swapped the car modules for Sierra 18-5107-1 pieces. Worked perfectly. I just bought two of them for spares for my 509s (still using the original modules from my 1998 MPI engines).

Jim, how are your engines coming along? I haven't talked to Ray in a while.

Snap, I was at his shop last week delivering a few parts for my engines. Getting closer for sure, they're getting ready to head your way for the Sebring race next week.


Thanks!!

I am pretty sure the GM Ram Jet modules are the same and likely better quality than most. I just bought a new GM distributor for the Ramjet as a replacement for my corroded original 502 MPI distributor. The new number for the distributor is 19420969. It is exactly the same as the original Merc distributor as far as I can tell. I am not seeing a number on the module that comes up online. You might consider buying the whole distributor as that module is going to be a good chunk of the cost anyway - I paid appx $350 from a GM dealer online. If it lasts 25 years like the original, most likely, it will be outlasting me.

I actually purchased two of the 19420969 earlier in the week, thanks!!