My car had a hypertech chip installed in the ECM. I'm installing a memcal adapter and a custom chip to get the thing going and I'm going to take it from there, but do I need to start with a stock PROM or would the hypertech be fine to plug into the memcal adapter?

Curious, I see the memcal adapter 'interrupts' the stock chip and it is used by the ECM instead of the chip that is plugged into the adapter. I see the two smaller chips in the PROM and apparently they are being used along with the new chip in the memcal adapter. What are the two smaller chips in the PROM for? Would there be any benefit of using a different PROM with a custom burned chip in my '88 350 TPI car? I have plenty of spare ECM's here, all with different PROMS. Thanks...

 

You want to use a 350 prom in a 350 and 305 prom in a 305. Those chips inside eprom are for limp mode and esc module I believe, and the limp mode is different per engine. Most of the memcals you get with 7730 ecm's are from v6 cars.
I'm sure you can use the chip you are using now on the adapter if it is working correctly now.