1991 OMC 4.3L HO SPITFIRE TO EST CONVERSION. NEED HELP.

[james44marine]

I have a 1991 donzi sweet 16' with a omc 4.3L H/O 4v engine. The spitfire system I've been told is starting to crap out.. Instead of wasting time messing with the obsolete spitfire system I have purchased a GM EST ignition convertion kit from Sierra P/N- 18-8835-1. My question(s) are as follows.
Has anyone done a convertion like this on this specific engine that could give me a a few tips? I'm aware that the spitfire coilpack/ignition module is responsible for the the shift interruption unlike the models that use the esa module for shift interruption. I'm unsure of how to to go about wiring this EST system to work with the shift interruption. Do I need a esa? Or can I convert the interrupter switches to momentary battery voltage supply to avoid adding a esa? If so can someone help me wrap my head around this nightmare. I have a complete manule with wiring diagrams for this engine along with the installation instructions for the est distributor kit. I'm just having trouble figuring this out and have searched on many forum sites for a thread someone has done this with a 4.3L HO spitfire convertion to est. Many are out there for 5.0/5.7/5.8/460/502 but not my engine. If anyone could please give me maybe a step by step of how to get this going? I would much appreciate it. Thank you.

 

[Lou C]

I would contact CDI electronics in Alabama. They make ESA modules for Cobras and I think the do make one for the 4.3 EST combination. I got one of theirs for my 4.3 that still has the points distributor after the original ESA quit working. This one will work with points or Petronix but not EST; that’s a different version.

 

[james44marine]

Thanks for getting back to me in such short time, I appreciate that. So if I understand correctly, trying to convert from the spitfire to a EST will not be possible inorder to achieve proper shift interruption operation?