Re: Newbi here from Cave Junction, Oregon.
 

That was my impression too that it may be a newer engine, what are the engine ID numbers? I may be able to clue in on the year if you can get them for me.

Re: Newbi here from Cave Junction, Oregon.
 

Finally got those number for you.

Here are the engine numbers. 305E 49292I

And here is the vin number if that helps. 1502HF1643B

Re: Newbi here from Cave Junction, Oregon.
 

So I just found out something weird. According to my Vin number my truck is a 1/2 but its a 3/4 ton. At least it has 8 lug axles. The bed is a chevy bed I believe because it has a chevy tail gate....but the cab is GMC and so is the front clip. More mystery. lol

Re: Newbi here from Cave Junction, Oregon.
 

If your truck was a 1/2 ton, the VIN would start with 1002. 3/4 ton VINs, like yours, start with 1502. See http://6066gmcguy.com/VinNumber.html.

The first truck listed here http://6066gmcguy.com/GMC-vin-list-6769.html has an engine number lower than yours, so that could mean that your engine is a 1967 or later.

Re: Newbi here from Cave Junction, Oregon.
 

(From Previous message) 1502HF1643B

No sir, your VIN does NOT indicate a half ton.
1500 Series is a "3/4 ton"
If it were a half-ton it would start with 1002...

15 = 1500 series (3/4 ton)
02 = 127" wheel base
H = Oakland, CA build plant
F = 1964-1966 (except that HF, yours, indicates a 1964)
1643 makes it the 643rd vehicle off the line
B = 6001 - 10,000 GVW

http://6066gmcguy.com/VinNumber.html

Re: Newbi here from Cave Junction, Oregon.
 

That's really weird guys cause according to this sight's vin decoder it says 15 means 1500 series 1/2 ton and 02 mean 127 inch wheel base. Thanks for the help though....what's the difference between the 1500 and 2500?

Re: Newbi here from Cave Junction, Oregon.
 

Ok, comparing several V6's that I have your engine I.D. number is closest to the 305E that came out of my 68 KM-2500. The number off my 305E is 497570 and yours is 492921, what looks likes an "I" in there is actually a 1. I would have to say you have an early 68 engine produced in the fall of 1967. One more way to identify a 66 and earlier engine also possibly 67's have a ridge on the left side of the block about 3-4 inches left of the oil filter assembly, 68 and up do not have this, it may have been a mounting boss for industrial applications, check if your engine has it.

Re: Newbi here from Cave Junction, Oregon.
 

In 1967 the model number 1500 became the new designation for half ton models. 2500 became the new designation for the 3/4 ton models. Prior to that (for 1966 and earlier GMCs) 1000 was the designation for half tons, 1500 for 3/4 tons, and 2500 for one ton models.

Re: Newbi here from Cave Junction, Oregon.
 

Thanks Ed.