Larger roof vent replacement.
 

Im just getting started on my first HI-Lo and am in the process of fixing the roof vents. The ac is intact sealed and works fine, but both of the vents have been broken and sealed over with glass and silicon. I think I have located several suitable replacement vents for the rear 14 inch vent, but the larger vent next to the ac appears to be 21x21 inches and Im having trouble locating a replacement for that size. Any one have any Ideas, could be im measuring improperly, or that that particular opening is referred to as a vent? Its on an 88 fun chaser.

I think you will find that yours is a 22X22 vent. This is a standard size but it is not as common as the 14X14 size.

Do an internet search for, "RV roof vent 22 inches," and you will see some results. Here is an example:
Elixir Vents.

Raul

The best prices for the vent is actually on Sportsman's Guide - Outdoor Gear, Military Surplus, Survival Gear and more go to Truck/ATV then RV vents. I have an 87 funchaser got mine for about $80.

I think what you are looking for is an escape hatch cover... if it has the little red handle , that's what it is.

If so, adventurerv.net has them for about $70.

Searching for a "vent" cover will pretty much not bring up a larger 22" escape hatch, only the 14" standard everyday vents, and a lot of parts places don't seem to carry them... most newer rv's only have the 14" vents in them anyways.

Added - remove the trim ring from the inside to measure the vent size.