I got a request from "johnnytugs1" about manuals for his 1977 Itasca C25C. His e-mail In-Box is "FULL" so I am posting the information here. It is a good example of what can be a confusing topic and is a good example of the level of detail one may need to resolve exactly what information aplies to a given configuration.
To start, you have one of the more confusing combinations. So pardon the long response and no, you are not pestering me. While I can point you to where the data is, you will have to deduce exactly what applies to you. Feel free to ask additional questions if need be. I already know you started your project over a year ago where you had a lot of water damage and everyone benefits from your relating how you solved problems. Your engine replacement pictures are great. I also suspect there is a interesting story behind the Water Heater splitting.
1. To organize the information on your computer make yourself a directory off the "My Documents" directory called RV.
Under the RV directory make yourself separate directories under that called "My Itasca", "Camping", etc. Under the Itasca directory make yourself several directories like Chassis, House, Furnace, Water Heater, Plumbing, etc. Just place relevant data in the appropriate folder so you can find it later.
2. Manufacturers like Winnebago purchase a standard chassis from a supplier (Chevy, GMC, Ford, Dodge, etc.) and build the house on top of that. There are separate manuals for the chassis, the house, and all the separate appliances. So, you end up with a whole lot of separate manuals. Additionally, the coach Mfg (i.e. Winnebago Corp) will typically build this years house (i.e 1977) on a previous year chassis (i.e 1976). However, while that may be typical it is not a hard and fast rule.
3. For your chassis: Chevy produced seperate manuals for each year. Chevy also combined coverage for Pickups, Vans, Step Vans, Blazer, and Class A P30 chassis information into these manuals under the monicer "Light Duty Truck".
In general, it is a 2 or 3 book set:
ST-330-YY: Service Manual [General info, adjustment, Remove/Replace Procedures]
ST-333-YY: Unit Overhaul Manual (Component Overhaul information after it has been removed from the vehicle)
YY = Year of the manual (74, 75, 76, 77, etc.
If the 6th digit of your Chevy chassis VIN "7" then you simply replace YY with 77
As shown at the following link, you can either buy separate paper books or the digital CD-ROM version that has both of them on it.http://www.faxonautoliterature.com/Search.aspx?c=48837
If the 6th digit of your Chevy chassis VIN "6" then you have to get the 74 manual set plus the 76 Supplementhttp://www.faxonautoliterature.com/Search.aspx?c=44791
Use the following EBAY link if you prefer that approach:http://motors.shop.ebay.com/i.html?_nkw=%2874%2C75%2C76%2C77%2C1974%2C1975%2C1976%2C1977%29+%28Chevy%2CChevrolet%29+Light+Duty+Truck&_sacat=&_odkw=%28Chevy%2CChevrolet%29+Light+Duty+Truck&_osacat=0&bkBtn=&_trksid=p4506.m270.l1313
Now fully decode the Chassis VIN to know exactly which chassis you have.http://www.chuckschevytruckpages.com/73-87specs.html
I am not sure if you have a P30 with a special cab or a G30 that the front sheet metal has been relaced by Itasca with a special fiberglass front end. It's not a stock van version nor is it a standard P30 Step-Van version.
4. For the Itasca house portion, Winnebago produced to 25ft Itasca Class C Models in 1977. The Mini C25C and the Seafarer C25CD versions. From the pictures I have seen of your rig, I believe you have C25C model. You do not have the blue accent line coloring on the side and grill.
1977 Common Parts Book: http://www.winnebagoind.com/service/wincd/1977/77common.pdf
Winnebago RV Parts and Accessories Catalog: http://www.winnebagoind.com/resources/manuals/pdfs/Winnebago_Catalog.pdf
Appliance Manuals require knowing the Mfg/Model # for what is installed.
Both 74 and earlier Eyebrow and 77-80 Winnebago coach manuals provide useful repair information:http://www.classicwinnebagos.com/forum/index.php?action=store;cat=46
They cover sheet metal repair as well as internal systems repair information. Both of these books would have assisted you when you repaired the overhead bunk area.