leaky heads gaskets, I'm losing it!

Alright, My 360 La motor needed new valve seals. I happen to have all the components to switch over to magnum heads including a set of heads. I figure, Why not? I made a hybrid for my 67 Dart years ago and it runs well. I'll do the same for the old D100. So I tear the motor down. Scrape the block with razor blades twice, clean with acetone, wire wheel the block and clean again. Put it all together and I have a coolant trickle in the front lower corners where the heads and the block meets right above the motor mount bosses. Ugh!!
So I tear it apart again. Take the heads and have them resurfaced just to be sure. Repeat the cleaning process, put it back to together and bam!! Same exact leak! WTF!! I've built at least a half dozen small blocks over the years and have never had this issue, let alone twice in a row. What am I missing? I'm using tried and true Felpro 8553PT gaskets. Everything is clean. New head bolts. The 1st time I torqued to 105'lbs like my magnum book says. Second time torqued to 95'lbs like my LA book says. The old heads never leaked. I'm at a loss. Am I using the wrong head gaskets? to mate the magnum heads to the LA block? Any help will be appreciated.