Re: How to fix this hole?
 

Fiberglass work is not hard to do. You can do the the repair, sand, and paint in one day. I agree with taking the side off, cut a piece of metal a couple inches bigger than the whole and use silicone caulk and DUCT TAPE to hold it in place on the back side while you do the Fiberglass repair on the visable side. Or find one with no hole in it or with the controls still attached to it.

Re: How to fix this hole?
 

If your A/C works; if your heater core doesn't leak, I'd steer clear of removing the case half. You will probably have to remove the entire unit in order to get this side off but if you are able to remove the one side, you will ruin the seal and have to take the other side off to replace it anyway. If you are going to add a vacuum canister, it could be used to cover any repair you make to the hole and if you only want to stop up the hole why not go to an electrical supply house (or maybe even Home Depot) and get a conduit plug which is used to plug unused holes in electrical boxes. Another alternative would be a plug used by plumbers to stop up unused holes in a kitchen sink. If you are insistent on removing the side, I think I have an extra one that has no breaks. I will have to look. If you need it let me know.

Re: How to fix this hole?
 

where i come from, poor workmanship is described as "when you get a wrinkle in your duct tape".

Re: How to fix this hole?
 

Some great ideas here guys. Thank you. Ill post back here when I decide what to do. I dont have a compressor on the engine so it will be heat only, I just dont want to take the stock parts off of the firewall in case I or someone ever wants to put it back to original later down the road. Again, thanks for all the help...

Re: How to fix this hole?
 

If you need to fix a hole like this you can use a hole saw to make the hole uniform. Then, using the same hole saw, cut a plug out of an old fiberglass cafeteria tray (or a new one if you think you can get away with it). The plug will be smaller than the hole by the thickness of the saw blade. The plug can be made to permanently fill the hole using two part epoxy to fill the gap. (JB Weld is an example, you can also buy fiberglas resin in gel form that works well also since it doesn't run so easily). This is easier than laying glass and painting on resin and repeating the process until you have the correct thickness.

Re: How to fix this hole?
 

Thanks for the tip Roland but its already fixed. It is thanks to you sending me a new cover. Thanks again!