If not foam, some little pieces of wood would work good too most likely... looking good, awesome when custom work turns out isn't it?

 

Have you tried a skim layer of body filler on it? Thats probly your best bet to get it looking smooth and flushed in, considering its real easy to build up layers and comes out alot nicer then just a fiberglass sand.

 

vinny: im doing the filler last to make it smooth. im trying to get it flush with the a/c now its about a 1/2 inch back.

oktain: yeah i loved seeing that thing fit in there and people saying it wont fit or im retarded lol proved them wrong. but wood pieces probably be to big.

okvortec: i was rethinking about what you said about fiberglassing it up but thats going to be my last resort. as long as that piece took and how impatient I am idk if i can do that, but if i must i will.

Ill post pics of what im talking about being flush with the a/c

 

Cool idea. Is the piece you made completely flat? Would there be any downside to just using a piece of sheetmetal or flat abs plastic rather than fiberglass? That way you'd have a nice uniform finish on the front. you can even buy textured or smooth abs sheets depending upon which look you prefer.