305 confusion

[62 Addict]

Please forgive me for asking, but I need some clarity. I did some searching & found some this series vs that series threads. None really said it all that I could find. This is mainly concerning light trucks. It looks like they came with A,D,&E 305's for different years. So, all the same block? Most parts should interchange? Like water pump, intake, heads, etc? I believe timing chain changed in about '69 due to cam journal?
Many people like me are getting these V6's and are confused when the different series are talked about like they are completely different engines. The huge weight differences on the V6 data page makes you wonder. Then you see they have pretty much the same specs.
I've been working on my own junk for 30 years: Chevy, GMC, Dodge, International, Studebaker, Olds, Pontiac, Ford & some foreign so I'm not a complete idiot. Not a genius, either. I've just never had a big V6. So all you V6 guys, could you help some new people out with some overall info? I got asked if a 305D & E took the same water pump. I could only guess. I don't have room for 10 GMC's to do research. I already have four trucks. The answer would make a good sticky. Maybe not the question.
Thanks,
Scott

[AZKen]

The "Sticky" is this whole website. The 16 forums, Jolly's info, the search functions, VIN decoder, archives, links, members.

Jolly's Legacy pages pretty much tell a lot that you want to know. All the 305's are the same stroke and bore, same compression as you said. Most, if not all parts are interchangeable even though the design for performance or strength may change. Here is a direct quote from the day (from Jolly's page) "Many major parts are interchangeable within all GMC V-6 engines to provide greater parts availability and standardization." When someone needs a specific part, they search the archives here or ask a specific question. Jolly does have a
"Known parts" list also. There are Guru's here to tell you what part to buy and where to get them. That's what the site is for. In printed form: That's what old parts books are for. That's how you get the "overall info." But most just want to know about a part for the truck they are working on.

I agree how curious the weight difference is..102 lbs from high to low.
Reason as follows:

1. Literature mistake
2. Casting/strength changes (wall thickness, passages, etc.)
3. Some weighed motors had/included accessories mounted, some didn't. (as in: short block/long block replacement motors)
4. Material changes. (pretty cool they have aluminum pistons)
5. Some may have been weighed with bell housing and clutch or automatic trans housing
6. Weighed in different years with different scales
7. I don't know, that has never kept me awake at night.

I guarantee that at least one of those answers is correct.

[bobdylan]

D and E about the same thing, A single barrel carb intake

[AZKen]

...and they use the same water pump. ACDELCO 252371 or AC Delco 252-371 or equivalent.


FIY: These water pumps do not seem to be available in the universe. A person should find a rebuilder on their own or buy one if anyone has them in stock. If you inquire, you will find they are actually Out Of Stock everywhere even though listed. The only place I see them is on Ebay and they are over $180 shipped. Better hoard them now! Last one I got was Amazon $49, then Rockauto $61..........all gone.

[62 Addict]

Ok. It doesn't really matter what letter. A 305 is a 305. Just minor differences per year like any engine.
Keep checking Amazon for water pumps. I bought one a month ago. Now I just need to get my 305 unstuck & running. My bore scope should be waiting for me back home.
Thanks for your help.

[kchampagne]

Hello from Littleton, CO! I believe this is the correct water pump:

https://www.summitracing.com/parts/g...5/applications

https://www.amazon.com/gp/product/B0...=ATVPDKIKX0DER

[AZKen]

I am still wary of those links. Amazon link says "usually ships in 1 to 2 MONTHS! Maybe they are not as hard to find as I thought. This place says 2 in stock and real cheap.
https://www.stockwiseauto.com/gmb-13...=all&Model=all
There is bad JuJu about Stockwiseauto on the web.
Thanks for the info Ken, that part number is a good search tool GMB 130-2835...I see that Scott /62Addict answered an AMAZON question about fit yesterday. Humm..

[bobdylan]

I have ordered gaskets from amazon, after a while get a refund saying not available, also place in Canada Monkey Wrench, talked to them on the phone, they said they could get them. one month later got a refund.

[kchampagne]

I ordered the water pump from amazon yesterday. They informed me that it shipped. Stay tuned.....

[AZKen]

Groovy, to say the least.