Im that guy with the automatic integra. Now that we are past that, i want to swap in a high compression B20 but also want to replace the transmission (140k). Could i use the b20 automatic transmission if it came on the longblock? Or would i need the stock da9 automatic transmission bolted to the block?
no, that trans will 100% not work. your trans needs to match your ecu unfortunately
What do you mean trans needs to match ecu?