Anyone driving an original 67 V6 305?

[Rick Mills]

I posted this question on the engine section of the forum but wondered if anyone viewing here has a 305 V6?
I had never seen one until today. It's in an original '67 GMC longbed.
It was pretty neat as the plugs and wires enter the head on the intake manifold side, not on the exhaust manifold side like most heads.
Just wondering if this was a standard option or something unusual?

[Longhorn Man]

chevy had the S series for inlines, e series for V 8... well GMC had the M series for the v6 trucks.
They were common at one time, but not so much anymore. There's few ppl here running them still though.

[CG]

I have one of those v6's, not sure on the size. Its in a 65. It runs and has a rebuilt carb. I tried to give it away, but no one wanted it, or it was too far away. We finally got around to stripping the truck. Keeping the auto trans and cross member. Rest is going to the scrapper. Seems like a waste, but Im tired of hanging on to all this extra stuff.

[ChevLoRay]

Weren't all of those V-6's 305's? Seems that they came out in the '60 models. Prior to that GMC used engines from different GM sources in their trucks. For instance, my '38 had a Pontiac 226 flathead in it. The Chevy had a 216OHV engine. I knew a guy who had a '57 and it had 347Pontiac in it. Larger models from GMC also used Buick straight 8's, back in the day.

Did GMC stop using the 305 with the introduction of the 68's or the '69's?

I understand they were torquey, but liked to guzzle the petrol.

[Spray-Bomb]

Originally Posted by CG

I have one of those v6's, not sure on the size. Its in a 65. It runs and has a rebuilt carb. I tried to give it away, but no one wanted it, or it was too far away. We finally got around to stripping the truck. Keeping the auto trans and cross member. Rest is going to the scrapper. Seems like a waste, but Im tired of hanging on to all this extra stuff.

It's prolly the too far away part, cuz free is my kinda price

[msgross]

I know a guy down the road from me with a mid 60's GMC with the V6, has a big 14bolt type rear too, all original.

[samwise68]

to my knowledge, the GMV V-6's came in several models of 305s, along with 351's, and even a 478, if i rememeber correctly.


http://www.6066gmcguy.org/

this site is going to have..well..basically everything you want/need to know about those old V6's.

enjoy!

-Sam.

[Longhorn Man]

up till 69, you could get the 305, and I think 68 was the last year for the 351.
GMC used there own engines for a long time, but after GM bought them, they started grabbing other engines from other divisions.
There was a 401 I think in the V6 too, and then the big V 12 that was 2 v6's together.
Some one will post a link to the jolly site here soon.. .all the V6 info you can handle.

[Longhorn Man]

HAHAHA!!!! I guess I am a slow typer!

[quickpm]

What's the bore size on the 305? Those pistons have to be huge.

['68 longbed]

I saw one opened up a while back, they look like those big "folgers" coffee cans.

supposed to be very torquey

[68GMCCustom]

I drive a truck that has one for now...soon to be replaced with a SBC. Its a '68 though, and has the 3sp. on the column.



I think I read somewhere that they consider this a big block V6:


great engines. make nice torque but not alot of hp. they are stronger then the straight 6's though.

[quickpm]

http://en.wikipedia.org/wiki/GMC_V6_engine

Pretty interesting, I didn't know there was a GM V6 in the 60's. The big 478ci was only 254hp, but with 442lb ft. I wonder what the gas mileage was. Of course, my Jetta is "only" 100hp, but it gets up and goes with 177lb ft. I have a great appreciation for "6's" now that I didn't have a couple months ago. If I could do it again, I wouldn't have bought the V8.

[68GMCCustom]

I'll trade you my V6 for a Vortec 350!

[quickpm]

Originally Posted by 68GMCCustom

I'll trade you my V6 for a Vortec 350!

Hehehe, I knew that was coming

[70gmcjimmy]

I am also pretty new to the v-6 stuff, but besides all the bigass stuff you guys are talkin about, there is that torque monster 702 V-12 GMC created by combining 2 351's. Ignition was fired out of one distributor with 2 6 cyl caps stickin sideways out of the main driver. Jolly has a great site.
I recently got a 62 K2500 with a 305E and I will never pull that out for sbc.

Later---DAC

[70gmcjimmy]

Originally Posted by Rick Mills

I posted this question on the engine section of the forum but wondered if anyone viewing here has a 305 V6?
the plugs and wires enter the head on the intake manifold side, not on the exhaust manifold side like most heads.
Just wondering if this was a standard option or something unusual?

Yah that is the way GMC designed these engines. Forgot to add that in my other response.

Later---DAC

[WorkinLonghorn]

What's the bore size on the 305?

Answer; 4 1/4 ". The 351 was 4.56".

[rwgregory]

I have an original '67 GMC w/the 305 V-6 and I love it. I used to have a '65 V-6 and I wouldn't mind getting another one as well. In my opinion the GMC V-6 is one of the coolest pure truck engines ever built. They don't like to rev much, but they have boatloads of low end grunt. What other engine will allow you to start in 3rd gear on flat ground without slipping the clutch??

['68 longbed]

i wouldn't mind havin one in a weekend warrior just for kicks. they are a cool motor to have.

do they make any performance cams or anyting for those?

[rwgregory]

'68 longbed: There are ZERO hi-po parts made for the GMC V-6. This is definately a "throwback" engine. The only way to light a fire under one is to modify other parts to fit it. Buick V-6 HEI distributors can be made to work with a little machine work, headers can be custom built, intakes and heads can be cleaned up with porting, you can bolt on a bigger carb and other than that, just use your imagination. In all honesty, they would make a lousy hot rod. If you try to get high RPM out of them they will blow up. They were designed from the ground up to grunt at low RPM. Use them as they were intended to be used from the factory and enjoy the ride...

[Bob B.]

I have a '67 with the 351. These engines have amazing torque at low r.p.m.'s. I have a 500 c.f.m. Holley 2 bbl. and a Pertronix ignition on it, and it does run better than it did stock. The last year for the 351 was '68, and the 305 was dropped in March of '69, but it was a dealer installed option through '72. The GMC V-6's were available in the 2 ton and larger trucks until '74.

[JAKES 68GMC]

Yeah, throw a 500cfm holley 2bbl. on one and it will wake them up a lot, but even then, they're still no hot rod.

[Big D]

I put around 35,000 miles on my 66 GMC 305 V-6 in college. Like everyone else has said they are torque monsters but definitely not hot rod material.
Around here there are still lots of grain trucks/dump trucks on the road equipped with the V-6.

I remember it not getting the greatest gas mileage, probably around 8 to 10 city, maybe 12 on the highway with a tailwind.

There used to be a local guy that had one running a set of homemade headers and glasspacks. It sounded pretty sweet.

['68 longbed]

would be a cool "odd" motor to play with. with that much torque maybe you could gear it up and make it more funner-er