Scored A Set Of Magnum R/T's!!!!!

Check out the latest Engine Master article on the 318.

http://www.popularhotrodding.com/tech/0810phr_chrysler_318_engine/viewall.html

They got 425hp out mildly ported Engine Quest heads,on a very similiar build you have,your R/T'S will out flow these!
Need to do valve guide to retainer clearance and I would go with the same cam...
Comp XE275HL. Specs for this stick come to 231/237 degrees duration at .050, and .525-inch lift with a 1.5:1 rocker ratio, all on a 110-degree lobe separation angle.Of course with the stock 1.6 rockers you will have .560-inch lift...
Here is an older article with 360 heads milled and same cam,which I am doing the same build with mildly ported J heads 2.02/1.60.....
http://www.popularhotrodding.com/enginemasters/articles/mopar/0667em_mopar_318_engine/index.html
OH,about your score....You luck dog !!!

I like the 275HL cam too but that older article shows that using 1.6s on such an aggressive grind can be a tricky proposition. On that occasion it actually cost power. I guess the lighter 8mm stem valves on the later build may have just edged it in the right direction.