Yes it is the sandwich type and i did the same porting and massaging on the adaptor passages as well. I could add bigger hose, but all the orificies in the adaptor and cooler with still be the same. -8 is damn near 1/2". What size are the oil passages in the block? I talked to Dearale for an extended time before i purchaced their cooler and questioned -8 be enough and they said it would be plenty. I had -10 in mind at the time.
I dont like oil coolers or just having external oil lines. Just asking for trouble, but last year when i posted my hot oil issues, seems like most everyone was suggesting a cooler. Now that i have one, seems not everyone is to hipp to it. I will make a call to Derale today and see what i can find out. As of now, motor has been to 7000rpm several times and still has bearings in it. 30# oil pressure hot. Thats better than it ever had without cooler.