Ironic as it's the sheet metal end tank version of your fmic that i'm looking at replacing. What is the difference in cores between gen1 and 2?

 

The same core is used between the gen 1 and gen 2 FMICs. The core has worked so well for us that there was no need to improve it. We pushed our time attack car to over 650whp with this core with no cooling issues. The major difference is the cast end tanks VS the older sheet metal ones. This offers better durability with improved flow over the sheet metal end tanks.