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This module came in a RamJet 350/502 distributor I installed in my TBI build:

Part # 1104060:
"Used on the fuel injected Ram Jet 350 and Ram Jet 502. Includes ignition module P/N 10482830, cap P/N 19166099 and rotor P/N 10477219." The module I pulled out of it looks like this and I can't confirm exactly what number part it is. I tried to find references to 28184533 but came up dry other than vague references to GM Marine Performance. It's definitely an 8 pin module so it's designed to be controlled by an ECM, which the RamJet engines come with.

Problem is that I get zero spark advance at idle, not sure how far up the RPMs lack of advance goes because I haven't tried it yet. Distributor base timing is set at 18* an confirmed with an Innova 3568 dial-back light. Commanded Idle SA in the tune is 28*. EBL WU Display shows 28* with the same +/- 2-3* fluctuations I see at the damper which only shows 18*.

The SA latency table in the tune has zero values from 400-799RPM, 800-1199RPM. It seems the key, according to discussions here and on TGO and a couple other places over the years stress the importance of these values to producing the desired advance accurately. If this thing has a weird latency curve and dwell time I'd need to find out and enter properly in the table. Otherwise, go with one that's pretty well known like the D1943A, D1965A or maybe even D1984A. A shame to toss a high dollar, perfectly good (albeit useless) ignition part into a drawer.

All the wiring is good from the ICM connector to the EBL ECM (B3, B5, D4, D5). The module tested as good at the local Advance Auto (as I suspected it would).

Anybody seen this module before and know anything about it??