60's GMC V6 - Boat anchor or not?
 

I bought a 68 GMC awhile back and to my astonishment it had V6 in it, I didnt even know they made a V6 back in the 60's but anyway and this thing was HUGE, if I remember correctly it was close to 350ci but looked more like a bigblock.
The motor ran fine but knocked like the dickens, the guy I bought it from had the entire engine rebuilt but something went awry in the assembly and it spun a rod bearing. This was just too much for the poor fella and he threw in the towel.
I gave him $800 for the truck and had it towed home.
The next day I pulled the pan and just for the helluva it, slapped a new insert on the rod.
Long story short it started knocking again so out it came.

I ended up sticking a junkyard 350sbc in it and selling the truck, I kept that big V6 for many years as a conversion piece in the garage but eventually hauled it off.

Question:

Does anybody on here know anything about these realics?
Are they worth anything? Or just another boat anchor from the past.

I heard famers used to use them for irrigation pumps cause they were so durable.
I was Just curious.

Heres what it looked like.

http://i187.photobucket.com/albums/x...carx111/V6.jpg


Thx, Cp

Friend of mine had one in a early 60's truck.Yep that motor knocked like a son of a gun.I was surprised one day he put oil in it and seen the size and it was a 6 banger...Never seen another one sense.

Friend of mine had one in a early 60's truck.Yep that motor knocked like a son of a gun.I was surprised one day he put oil in it and seen the size and it was a 6 banger...Never seen another one sense.

Thx Chris, sounds like they were pretty few and far between.

They were pretty common in early to mid 60's GMC trucks & busses. The smaller ones in pickups were 305 cid and the bus models were 351cid and bigger. Yep they are huge and heavy and hold 6-8 gallons of coolant.

I rebuilt one for a customer about 6 years ago. There must be an inch of deck between the cyls, 4 ring pistons, really long con rods, and they redline at around 3600 rpm.....built like an industrial engine and make a bunch of torque compared to a 305 v8.

Boat anchor? In the real world, yes, but kinda cool just the same......
Johnny

sounds like they were the first ones and had problems that now
have been solved and these relics even rebuilt have problems,
i have never seen one, and it does look like a big block.
when i was a kid in the 60's my dad had a gravel truck and would
haul dirt and rocks, all over the hills in texas, that truck would
run great with a load. i helped my dad change the oil before a
long delivery and the truck had a straight 6, told my dad, "a
6 cylinder" he laughed and said, "a heavy duty 6", man that
truck was big with duelies and it would haul, it had a 6 :? :shock:
i guess with a good trans and rear the 6 worked great

man, that take,s me back a lot of years, i worked for a olds-gmc dealer as a teen, mid 60,s. shop truck was a v-6 gmc, 1965 i think, tq, was not bad but no top end, as i recall the thing shook like the balance was off.

I WONDER IF THEY MAKE A STROKER KIT???????????????? :roll:

My curiosity got the best on this one and I'm impatient which led me to do some reasch on this oddball engine.

I found quite a few different versions.

They were used primarly as a bus/heavy duty truck motor but they did manage to find their way into quite few 1/2 ton pick-ups due to a V8 engine shortage in the mid sixties.

The engines were produced from 1960-1974

The largest of the V6's was a mind numbing 478ci :shock: with a bore of 5.125 inches and a minuscle stroke of 3.86 it was all torque.
Peak Hp was only 254 but torque was a very respectable 442 ft lbs @1400rpm.

Everything on these motors was overkill, shaft mounted rockers, thick decks surfaces, large journal forged crankshafts, smoothed combustion chambers to reduce carbon deposits, weight matched forged rods and 4 ringed pistons coupled with large capacity cooling systems and high volume oiling, these engines were built to last.

GMC marketed them as a low maintenace 200,000 motor.

GMC also made a V12 or a twin six, it looked like two 351 V6's mated together, but it was all one block with one crankshaft and one cam.
It did have four separate heads, four exhaust manifolds and 2 intakes.
Dsplacement 702 cubic inches! Hp was still down @ 275Hp but again torque was king @ 630 ft lbs.

Though it was used primarily in industry and in a few large trucks some crafty folks shoe horned them into some pretty neat stuff.

Click on the link to see the multitude of things these strange motors have powered.

http://www.6066gmcguy.org/V6powered.htm


Have a good weekend, Cp

That is really cool. I've never see those before. Well, if I did I didn't realize it anyways. I've talked to a couple old farmers about those and they said the same thing. That engine is a work horse. I love those v-16's. That Blastolene is SICK.