Frame Year Identification

[Desert_Eagle02]

Hey guys, I have a couple questions about identifying my frame year. The truck is a '78 K20 long bed. But I think the frame might actually be a '75 or '76. It has the '76 and earlier tie rod set up and a '75 or '76 radiator support and grill and hood latch assembly. Anyway, I'm looking into putting a lift on it and the kits are different between a '75-76 and a '78. Is there anyway to tell for sure what year or style frame it is? Also its supposed to be a K20 but if it had a frame swap is there a way to tell if it is? Are the leaf springs wider or something? It has 52" springs. I need to know that for a lift kit too.

Any help will be appreciated, thanks.

[tucsonjwt]

Keith Seymore might chime in here, but on my 83 there is a number stamped on the right (passenger side) frame rail near the cab. It is stamped on the top side of the frame, so you would need an inspection mirror to read it, unless the bed is off the truck. I don't know how to interpret the numbers.

[KrazyRay]

Your vin could be on the frame rail by the steering box, but the later years have it under the cab on the passenger frame rail. The number before the letter that identifies the GM plant will be the year...4Z= 1974 built in Fremont, CA.

[Desert_Eagle02]

Thanks for the reply guys. I searched the frame rails all over in the engine compartment on both sides, and the passenger frame rail under the cab and bed using a mirror. I couldn't find anything. I guess I'll call different lift companies and see what the difference is, or roll the dice and assume its a '75 or '76. Perhaps one day when I do a frame off I will run across the vin numbers. Anyways thanks again.

[Jstock85]

Would it be the VIN number on the frame or a standard GM 8 digit part number stamped?

[77 ChevySport]

FWIW: Picture below is of my frame number. It is in plain site right under
the driver's seat. Number is for a 1977 frame. My truck is a 1977 stepside
shortbed. Larry

[Jstock85]

good info. Thanks Larry!