Engine Serial Number

[Farmer Dean]

Just bought a large Hyster fork lift with a V6 305 in it. Engine Serial Number is 305C 534051. Is there any way to tell what year this motor is? No plates on the forklift.

[Jeannie]

Welcome to the forum Farmer Dean.

According to Jolly's site the 305C was used in 1960 and 1961. We would love to hear the story of your forklift and see a few pictures for the club if available.

Have a great day,

-Jeannie

6066 GMC Club

[bigblockv6]

The only one that's good on identifying the year of a V6 by the serial number is Lewis Matkin. Otherwise look at some of the casting dates on the intake manifold and exhaust manifold, if original they will give you a close ball park figure of what year the engine is. The 305C was manufactured from 1960-74 not 60-61.
:lolsmack2:

[Farmer Dean]

Thanks for the replies, found a 10/22/69 on the exhaust manifold; assuming they manufacture a production run of manifolds before the need them, my motor is probably a 1970? Comments?

[oldtrucksters]

According to an old AERA engine and head identifier book. 1969 is it. 305 block model e and c 515000- 536000.

[bigblockv6]

It could have very well beem an engine that was manufactured in the 1969 model year run that was left over to be used in the 1970 model year, that would explain the later dated manifolds.

[Farmer Dean]

Very good sleuth work folks, thank you for the help. Farmer Dean

[jagarra]

The only one that's good on identifying the year of a V6 by the serial number is Lewis Matkin. Otherwise look at some of the casting dates on the intake manifold and exhaust manifold, if original they will give you a close ball park figure of what year the engine is. The 305C was manufactured from 1960-74 not 60-61.
:lolsmack2:

BigblockV6, This brings up an interesting point. If I look at a Motors Manual for our vintage of trucks I see that the letter on the engine codes changed from year to year. My 62 has a D block, previous had C and subsequent years had E models. Did GMC just use blocks from inventory willy nilly or was there some sort of sequence in the letter changes and use of the block.

I sort of always assumed that the letter changes followed the years of production, appears that is not correct.

[Ed Snyder]

If I look at a Motors Manual for our vintage of trucks I see that the letter on the engine codes changed from year to year. My 62 has a D block, previous had C and subsequent years had E models. Did GMC just use blocks from inventory willy nilly or was there some sort of sequence in the letter changes and use of the block.

I sort of always assumed that the letter changes followed the years of production, appears that is not correct.

This page from Jolly's site has a lot of info: http://6066gmcguy.com/EngineData.html but doesn't include dates available for all the different variations of the V6. But the letter designations had little to do with the years of production. The "C" version, standard in the bigger trucks, was a heavier duty engine than the versions available in the light duty trucks.

[bigblockv6]

Previous to the "D" block designation it would have been the "A" for 1960 and some 1961 models, the "D" was introduced in the 1961 model year as well and the main difference was it was a 2bbl version rather than 1bbl and ended up replacing the "A" version all together by 1962. Like Ed Snyder said The "C" version was a heavy duty version used in bigger trucks, it had the longest run of all the GMC V6 engines for 15 consecutive model years up through 1974.:thumbsup:

[FetchMeAPepsi]

Hey everybody! Mine's a D and she's from 1962. I looked at that page and in the notes section it says C models were 1960 and 61 in big trucks. (note 2).

If thats wrong we should get it changed! :thumbsup:

[bigblockv6]

Hey everybody! Mine's a D and she's from 1962. I looked at that page and in the notes section it says C models were 1960 and 61 in big trucks. (note 2).

If thats wrong we should get it changed! :thumbsup:

That's definitely wrong!:pullinghairout:

[FetchMeAPepsi]

That's definitely wrong!:pullinghairout:

I guess someone needs to find out what the real dates were and pm jeannie so she can fix it. :getrdone2:

[6066gmcguy]

The info on the site states "Used in 1960-61 in series 4000 trucks" that means this was the one of two Engine use in these trucks as note #2 in on both the 305B & 305C engines. Don't read anything into the notes that is not there. also note 4 "The 305C was the same as a 305B except for manifold and carburetor which provide increase horsepower".

Notes were posted to the page as I found the info, no were in the notes does it say the 305C was dropped from the line up.

[FetchMeAPepsi]

The info on the site states "Used in 1960-61 in series 4000 trucks" that means this was the one of two Engine use in these trucks as note #2 in on both the 305B & 305C engines. Don't read anything into the notes that is not there. also note 4 "The 305C was the same as a 305B except for manifold and carburetor which provide increase horsepower".

Notes were posted to the page as I found the info, no were in the notes does it say the 305C was dropped from the line up.


Ahh ok. It reads different when you're looking at it. I understood "This motor was used only in 1960 and 61 in big trucks, that's all." And since mine is 1962 with a D it made sense to my simple brain! :D

[6066gmcguy]

FetchMeAPepsi, your truck is a light truck, a 1962 so the engine it should have is the 305D, which replaced the 305A in the engine line and the 305A was dropped after the 1961 model year.

Here is what you need to know about 305 V6 Engines,

305A 1960-1961 light duty engine.
305B 1960-1961 Med Duty truck engine
305C 1960-1974 Med & Heavy duty engine.
305D 1962 Light Duty engine. replaced 305A
305E 1963-1974 Light & Med duty engine. Replaced 305D.

Light duty engine had 3 piston rings, heavy duty had 4, but some light duty engine have been found to have 4 rings as well.

Light duty trucks 1000-3500 Most used the 305, with the 351 as an option.
Med Duty trucks, 4000-6000 you could find 305, 351 or 401 egnines in these trucks.
Heavy Duty trucks 6500-9500, most of these had the 401 or 478. 7000 series had the 702 V12 1960-1965.

All GMC Images & material contained on the WebSite were taken from publicly available sources provided by GMC to promote their Trucks from 1959 to 1974.

[6066gmcguy]

FetchMeAPepsi, your truck is a light truck, a 1962 so the engine it should have is the 305D, which replaced the 305A in the engine line and the 305A was dropped after the 1961 model year.

Here is what you need to know about 305 V6 Engines,

305A 1960-1961 light duty engine.
305B 1960-1961 Med Duty truck engine
305C 1960-1974 Med & Heavy duty engine.
305D 1962 Light Duty engine. replaced 305A
305E 1963-1974 Light & Med duty engine. Replaced 305D.

Light duty engine had 3 piston rings, heavy duty had 4, but some light duty engine have been found to have 4 rings as well.

Light duty trucks 1000-3500 Most used the 305, with the 351 as an option.
Med Duty trucks, 4000-6000 you could find 305, 351 or 401 egnines in these trucks.
Heavy Duty trucks 6500-9500, most of these had the 401 or 478. 7000 series had the 702 V12 1960-1965.

All GMC Images & material contained on the WebSite were taken from publicly available sources provided by GMC to promote their Trucks from 1959 to 1974.

[bigblockv6]

The 305D came into play in 1961, you could get the 305A or the 305D that year. By 62 it was just the 305D:lolsmack2:

[FetchMeAPepsi]

FetchMeAPepsi, your truck is a light truck, a 1962 so the engine it should have is the 305D, which replaced the 305A in the engine line and the 305A was dropped after the 1961 model year.

Here is what you need to know about 305 V6 Engines,

305A 1960-1961 light duty engine.
305B 1960-1961 Med Duty truck engine
305C 1960-1974 Med & Heavy duty engine.
305D 1962 Light Duty engine. replaced 305A
305E 1963-1974 Light & Med duty engine. Replaced 305D.

Light duty engine had 3 piston rings, heavy duty had 4, but some light duty engine have been found to have 4 rings as well.

Light duty trucks 1000-3500 Most used the 305, with the 351 as an option.
Med Duty trucks, 4000-6000 you could find 305, 351 or 401 egnines in these trucks.
Heavy Duty trucks 6500-9500, most of these had the 401 or 478. 7000 series had the 702 V12 1960-1965.

All GMC Images & material contained on the WebSite were taken from publicly available sources provided by GMC to promote their Trucks from 1959 to 1974.


:ahhhh: Now that's a buncha info! I could listen to you guys talk about engines all day. Makes me even more proud to be part of the club :yourock:


And now I really wanna get back to work on Cecilia... Only one more fence panel to go, then erect my shed, and BOOM - back to work on my baby!

[Jeannie]

I believe this is now fixed in the notes section of the Engine Data page. I will further clarify the page on the site renewal in the coming months as time allows.

[Paul Bunch]

I am trying to find out what year and size V6 GMC engine a friend has and all I have to go on is the engine number. The number is WG2 247G675 the engine is running a hammer mill and has not been in a truck for years. Any help is appreciated.

[bigblockv6]

Doesn't sound like an engine serial number, the correct engine ID number is below the front right bank cylinder head, thee is a machined boss were the number is stamped and the first 3 digits will be the displacement of the engine.

[bigblockv6]

Doesn't sound like an engine serial number, the correct engine ID number is below the front right bank cylinder head, thee is a machined boss were the number is stamped and the first 3 digits will be the displacement of the engine.

The numbers you supplied seems to be cast into the block as part numbers the 247 prefix is definitely a GMC part number of that era, like I mentioned previously the engine ID number is stamped. The numbers after the displacement may give a clue to what year it is. Lewis Matkin is the only one that can determine the ballpark figure of the year by those numbers. You may want to look at the intake and exhaust manifolds, there's dates cast on them that will also give you a ballpark figure on what year the engine is.

[AZKen]

Paul, BBV6 advised earlier in this post to check intake and exhaust manifold cast numbers. Is that what the number is from?

[Paul Bunch]

The engine belongs to someone else and he gave me the number so I do not know at this time where he got it. I will try to get the proper number later. Thanks