4X4 Frame Identification

[Tdrcreyn4]

I have a 1969 K-20 that started it's life as a two wheel drive. Is there a way to positively identify what the donor rolling 4x4 chassis came out of? It appears as though they took a complete unmodified rolling 4x4 chassis and just replaced the body and bed. The chassis has and open knuckle Dana 44 up front and an Eaton in the back but not sure if it is a HO52 or HO72. Front power drums / long bed if that helps. Any thoughts or help would be greatly appreciated. Thanks.

[sboris]

Sounds like a 69 or 70 to me. Get the number off the top of the rail by the steer box and see if this helps.
http://outintheshop.com/vin_decode.html

[57taskforce]

If its got open knuckle drums than at least the front axle is from a 1970. As said above the partial vin by the steering box will give you the model year.

[Tdrcreyn4]

Thank you very much. I'll look there.

[Tdrcreyn4]

OK, here is what I have so far. Can anybody give me a sanity check with serial number identification? This time with pics. What I think I have determined so far is this:

The front axle is a Dana 44 and has a ratio tag listing 4.09 gears. I found the Bill of Material # (attached) and it is 603036-9. I found a BOM Table and it said that the axle was from a 1970 K20, standard axle with 4.09 gears.

I still can't figure out if I have a HO 52 or HO72. Everything points to an HO52. I found the serial number which is (TPW 120862) I found a reference to the build codes on these axles and it appears that it also came originally from a 1970 K20. What I found is that the HO52 came with 4.10 gears in the 3/4 ton, 350 automatic K20. The only thing that is throwing me off here is that the driver side of the case has an adjustment bolt that I though only came on the HO72?

As for the frame, I have had no luck. There are no numbers on the top of the frame rail on the driver's side that I can find. Were they stamped or raised letters? Clearly, I don't plan to remove the cab at this point to find the other numbers. The only number I can find is stamped on the side of the frame (attached pic) Not sure if that means anything at all?

Lastly, I found the engine casting number on the back of the block on the drivers side. It is 3955272 P. I was able to find something on the internet that said it is a 1969 396. I can't find a serial number anywhere on it. I did find some numbers on the side above the oil filter that say HI PERF PAS K 21. Based on what I have been able to find I think this is a 1969 four bolt main that came rated at 375 HP originally?? I think it was cast between Jan 7 and Mar 17, 1969. The oil gallery plug is 3/4 in and the hole to the left of it is 1/2 in. (see pic).

Basically everything I see points to a complete 1970 K20 rolling frame rebooted with a 1969 C20 body. Don't know about the motor. It also has a TH400 and NP205.

Thoughts or comments would be greatly appreciated.

[Bigdav160]

Almost certainly the axle is HO52. Many of those also had the load bolt on the pinion.

I don't see any partial VIN stamped numbers on my frame either. The ones you posted could be part numbers.

The big block has a pad with suffix stamps like a small block. Decoding that number will help identify the engine.

I'm going to add, it seems 375hp blocks had two ports, drilled through, tapped and plugged, for oil cooler lines.

[57taskforce]

ill see if i can get a picture of the location of the vin on my 72 K/20. As far as i know there were no Turbo 400s in the K trucks either but i could ne wrong. The vin on the frame should be stamped

[sboris]

Heres what i got. The number is right across from the front of the block. Across fro the power steer pump. Stamped. I have heard of trucks that dont have this.. Wire brush it with a bright light. Mine is a 70 built in Janesville.

[Tdrcreyn4]

Shawn, Thanks for taking the time to send the pic and comment. Todd