[RICK LAKE]

Motorhead Ted when you get this thin with trying to seal 2 parts togeather and both are aluminum, you come out with leaks alot of times. Unless the block,heads and manifold where all machined to match angles and surfaces, you could have a problem. IMO a 1/16" is not enought of a edge for a seal to last more that say 20-50 heat cycles. Adding a sealer like Hi-Tac will help to seal the thin edge if this is on felpro 1247 gaskets
The best thing is to go to a welder first and have them tig a wider lip around the intake manifold. For the heads you want to go in about 1.5" and just Smooth out the port a little to match the intake. Leave the bottom of the port alone. You get little to no added flow by porting at the bottom.
Most of the power from head work is around the valve stem area. There are numbers of about 85-89% of the port to the valve size. This will get you the best numbers of flow and have the motor still make good power low in the idle to 2,500 rpms.
It might be better to have a pro do this like Keith Craft. CNC the heads for you and do the match work on the intake. It is easy to grind a thin wall of a pushrod hole. I have done this on a edelbrock set of heads for another brand. It look easy but takes alot of time to get right. Get it right you are a hero, get wrong and the repair could be hundreds. If you have done this before, try it but, watch out for thin walls. I have seen tubes needed on the FE head when guys on both forumns thought they could do port work.
If you are looking for power, how are the side pipes?? Rick L.