1983 GMC Astro cabover restore and semi work

I have a 1983 GMC Astro cabover I had for a few years and slowly fixing it up when I have time to. It is a full size cab with a single axel. If I remember I bought it for only $2000 and was used just as a yard truck. so has very low miles. Company owners said should just have to put new batteries in and change the fluids and should start up. From what I can see someone in the yard backed a trailer into it just scuffing the driver side and breaking off the turn signal light and cracking the driver side windshield. That was the only damage and just parked it probably due to the windshield.

So far I bought a brand new turn signal light and put it on and got all 4 GM factory manuals including the 6" thick GM parts catalog book where I can find all parts numbers for this truck. This truck also came with all original purchase papers and build order sheets. Replaced the elbow with a new one. Also just been cleaning it up, I even got out the factory GMC grill weather cover and put on. I am now in the process of ordering a driver side windshield and looking for 4 new batteries.

Now I am trying to keep everything on this truck GM as much as possible, So I want to see if they make the large batteries from AC Delco still witch from my book shows they still used AC Delco in the heavy duty trucks too. I also need to find what type oil filter it uses and if that I can find one anymore. The place I bought it from said it has a Cummins big CAM 350 but the data sheets shows it has a NTC Cummins big CAM 300. The data plate on the engine looks to fallen off as they were riveted on. I called Cummins and said I can find a 8 letter serial on the block witch I still have to find and they will mail me a new data plate.
I have been also looking for the original GMC Trucks white mud flaps witch is impossible to find online anywhere.

I've been searching online trying to see what GM makes in trucks today and from what I remember GM discontinued the Astro, General and brigadier in 1989 fully. All I can find today from GM is just Medium duty trucks such as box trucks. http://www.gmfleet.com/chevrolet/low-cab-forward-trucks.html

So when I get time to, have the money but need time I am going to drain the oil out and change it, drain and put in new anti freeze. Drain the old diesel fuel out and put in new fuel, been sitting for a few years. This truck is getting restored and will be used for temp work such as a gravel getter with a small dump trailer. I already tried to get classic plates for this but in PA I guess they said they don't make classic plates for big trucks, and a normal plate cost $1600, at least that's what the notary told me. Live in PA.

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