67 twin turbo dart

As for coil dwell, go with what the coil manufacturer recommends, not what MegaSquirt recommends. I used an aftermarket coil on our Jeep. Bench testing the coil, I got optimal spark at around 2.1 ms dwell (way less than your 3.5 ms). The Jeep ECU outputs a stock 2.8 ms. The additional dwell overheated the coil & fried it.