69 gmc dually big v6

[tlwilliams]

hello everyone,

im currently in a pickle and once again turning to the experience here for direction, i have a 69 gmc dually with the big block v6 engine. i currently have the truck for sale but little luck with the corona virus setting in, im also debating on cummins swapping the truck and have a donor picked out. But i guess my real question is, how rare is this engine? should i keep it with the truck? it runs really well just lacks modern day power and drivability, its pretty much a 50 mph truck.

i will attach a couple pics when it lets me, currently it will not let me add any, thanks for any insight!

[tlwilliams]

a few pics, the forum is being funky with my post. sorry for inconvenience

[geezer#99]

If it runs good, keep it.
Lots of info and upgrades here.

http://6066gmcguy.com/

[tlwilliams]

Yeah I’ve been all over that website , the engine is definitely cool, just not sure it’s my cup of tea. If I kept it I’d want to use it to pull my other truck to car shows

Originally Posted by geezer#99

If it runs good, keep it.
Lots of info and upgrades here.

http://6066gmcguy.com/

Posted via Mobile Device

[maverickmk]

If it were mine, I would put a 454 in it.

[truckster]

Which V6 does it have? Is it a factory dual rear wheel? It might be a very rare truck, but looking at the hood, it's definitely been modded to some degree. If you have the SPID, that would be a good place to start.

[tlwilliams]

I believe it’s the 305ci model , the rear end is not factory to my knowledge they didn’t make a dually light duty till 73.

Silly question what’s the spid?

Originally Posted by truckster

Which V6 does it have? Is it a factory dual rear wheel? It might be a very rare truck, but looking at the hood, it's definitely been modded to some degree. If you have the SPID, that would be a good place to start.

Posted via Mobile Device

[71gmcC15]

the rear fender looks like it is from a 73 up dually

[tlwilliams]

That’s what I thought as well , rear end looks to be a Dana 60 but haven’t investigated to hard

Originally Posted by 71gmcC15

the rear fender looks like it is from a 73 up dually

Posted via Mobile Device

[maverickmk]

Originally Posted by tlwilliams

I believe it’s the 305ci model , the rear end is not factory to my knowledge they didn’t make a dually light duty till 73.

Silly question what’s the spid?

Posted via Mobile Device

SPID is the label on the inside of the glove box door listing the options for the truck.

http://67-72chevytrucks.com/vboard/s...highlight=spid

[72 k15]

Maybe try and figure out the gearing or a overdrive trans and you would likely be able to go much faster. I would keep the v6

[MJN]

Keep the V6, the engine isn't keeping it from going faster then 50mph, the rear axle ratio is most likely your limiter and probably causing the engine to run high RPM's. Also, factory dually (dooley) trucks were available prior to '73 but not as fleetside pickups.
It looks like someone swapped in the rear axle and did lots of other work. A picture of the rear axle would be helpful as well to help identify it. Did this truck start life as a 1-ton?

[tlwilliams]

The truck is a c20 , I think the engine is the problem with the speed or at least with the current setup , as I have plenty of rpm left just no power to go after faster , I can floor it and will do about 55, trans is a SM465

Originally Posted by MJN

Keep the V6, the engine isn't keeping it from going faster then 50mph, the rear axle ratio is most likely your limiter and probably causing the engine to run high RPM's. Also, factory dually (dooley) trucks were available prior to '73 but not as fleetside pickups.
It looks like someone swapped in the rear axle and did lots of other work. A picture of the rear axle would be helpful as well to help identify it. Did this truck start life as a 1-ton?

Posted via Mobile Device

[tlwilliams]

glove box pic

Originally Posted by maverickmk

SPID is the label on the inside of the glove box door listing the options for the truck.

http://67-72chevytrucks.com/vboard/s...highlight=spid

[tlwilliams]

Yeah I’ve been all over that website , the engine is definitely cool, just not sure it’s my cup of tea, I either want to swap the truck or sale it I think. If I kept it I’d want to use it to pull my other truck to car shows

Originally Posted by geezer#99

If it runs good, keep it.
Lots of info and upgrades here.

http://6066gmcguy.com/

Posted via Mobile Device

[truckster]

Originally Posted by tlwilliams

I believe it’s the 305ci model , the rear end is not factory to my knowledge they didn’t make a dually light duty till 73.

Silly question what’s the spid?

Posted via Mobile Device

Sorry. SPID is Service Parts Identification Decal. I see you found it.

I would say the truck is somewhat rare only because the 305 V6 is becoming pretty rare.

[LockDoc]

Originally Posted by tlwilliams

The truck is a c20 , I think the engine is the problem with the speed or at least with the current setup , as I have plenty of rpm left just no power to go after faster , I can floor it and will do about 55, trans is a SM465

If it has an SM465 and the transmission to bell housing bolt pattern is the same as Chevy (I don't know anything about the V6's) and you decide to keep it, do this.....

http://67-72chevytrucks.com/vboard/s...d.php?t=673588

LockDoc

[72 k15]

Personally I would keep the engine, but if you do want to get rid of it Put some new plug wires tune the carb and maybe a rotor and then if it is still so lame you can’t handle it think about doing gearing or overdrive trans or even a new engine.

[kwmech]

Grew up with a 69 GMC with a 351 V6 and a 465. It was a strong truck and a stump puller. I think it averaged 6-7mpg. Top rpm on the engine was 4k. Anything over 3k I'd swear you could watch the fuel gauge move. A 5th gear would be a huge improvement but personally, if I came across another one of these I'd swap out the engine. Looking at a huge V6 is cool, but living with it is another.

[truckster]

I had a 305 V6 in a 66 GMC. It wasn't a race truck, but it would haul anything. In fact, it towed my father-in-law's boat better than his Ford truck with a 390 did.

You might want to figure out what gear ratio you have in the rear end before you make any decisions.

[tlwilliams]

thats an excellent way to word it, i love having it in there and being able to show ppl and create conversation, but damn driving it sucks lol

Originally Posted by kwmech

Grew up with a 69 GMC with a 351 V6 and a 465. It was a strong truck and a stump puller. I think it averaged 6-7mpg. Top rpm on the engine was 4k. Anything over 3k I'd swear you could watch the fuel gauge move. A 5th gear would be a huge improvement but personally, if I came across another one of these I'd swap out the engine. Looking at a huge V6 is cool, but living with it is another.