I could have sworn I read a few months back that on the speed density TPI (90-92), the ESC module was soldered onto the memcal and was the same between the 305 and the 350. The only difference between the two configurations is the knock sensor which looked for a different knock frequency. The output from the sensor would be the same in both the 305 and the 350 so the ESC would work for both. Following this, I remember people saying that only the knock sensor needed to be swapped for speed density cars, while MAF cars needed a new ESC along with the new knock sensor.

Searching around again today to confirm my memory, I can't find anything that would confirm this. Most posts are for MAF cars or TBI cars. Can someone let me know if I need a new ESC module on top of the knock sensor I had already planned to buy or can I just reuse my ESC module from my 305 computer?

 

For speed-density applications, the ESC function is handled by the ECM. As you stated, the interface module is piggy-backed onto the MEMCAL instead of being firewall mounted as with the MAF applications.

You should only need to connect the correct knock sensor for the engine. The 305 KS is more sensitive than the 350 KS.

If you are installing a 350 SD you can abandon the old ESC and use the harness from the SD setup. If you are re-pinning the MAF harness for SD there will be some rewiring involved to bypass the original ESC.