GMC vs Chevy differences

[bpmcgee]

Has anyone catalogued or know of a catalog of the specific differences between GMC and Chevy trucks of this generation?

I bring this up because I was looking through the 60-66 GMC/Chevy Assembly Manual and noticed there wasn't anything about GMC in there. No RPO codes for the 305 V6, no paint codes, no pictures showing the different instrument cluster.

I found the 6066gmc page (http://6066gmcguy.com/GMCvsChevy.html) but that's very broad strokes.

B

[1963c-10]

GMC had their own service manuals.

[bpmcgee]

Yup, I saw those. I haven't put eyeballs to one yet, but they don't usually cover things like available dealer options, paint codes, etc.

B

[1963c-10]

I probably have some literature on those codes. Will look this weekend.

[TJ's Chevy]

The original red for the 305 is not produced. Closest thing to it is...dare I say....f$$d red, or the safer route of Cadillac Red.

[Praxiss454]

Originally Posted by TJ's Chevy

The original red for the 305 is not produced. Closest thing to it is...dare I say....f$$d red, or the safer route of Cadillac Red.

I heard Chrysler Red Duplicolor DE1632. I bought a few cans and so far have painted an alternator bracket (which may not have been red in the first place but too bad for it.)

You'll find Aerotruk has posted several images of GMC service options. If you look through my truck thread (linked in my sig) he has posted many of them in there.

[TJ's Chevy]

My bad, I meant Chrysler Industrial Red. Don't know where Caddy came from. haha

[60-66]

There have been several discussions about all the differences between GMC and Chevrolet. It would still be nice if there was a dedicated forum here for Restoration and preservation of original trucks. While I like modified trucks , the restoration or factory details discussions are LOST on this site. The only section we have here is one continual thread. That thread is very difficult now to find anything in without spending a lot of time going through every page. They made a special section for Panels and Suburbans in the last few years but still no restoration or preservation section. I personally know of MANY here that feel the same way.

[jbgroby]

mainly, they were cosmetic.

Different dash top.
Different face on the radio (GMC on glass front).
Different glove box door, due to dash top.
Different tail gate lettering of course.
Barbell on the grill (4 headlights for the entire 6 year run).

You could get all the same options and they were for the most part inter-changeable.

[bpmcgee]

Originally Posted by jbgroby

mainly, they were cosmetic.

Different dash top.
Different face on the radio (GMC on glass front).
Different glove box door, due to dash top.
Different tail gate lettering of course.
Barbell on the grill (4 headlights for the entire 6 year run).

You could get all the same options and they were for the most part inter-changeable.

JB,

Actually you couldn't get the same options -- you couldn't for instance, spec a GMC with the V8 or a Chevy with the 305 V6. And since they sometimes adjusted the rear-end gearing to match the engine, it's possible they came with different gears. And the clutches won't interchange between those two. And the GMC had a hydraulic clutch actuator, which means the master cylinder is going to be dual instead of single.

That's what I want to catalog.

Before I actually owned a GMC I thought as you do -- now I'm seeing that they aren't as interchangable as I assumed, and I wonder if anyone's written down this stuff.

B

[jbgroby]

Sorry, I was not thinking alone the lines of Engine and trans. I 'think" (could be wrong) that both lines shared the inline 6's?

Chevy of course had the inline 6, and V-8
GMC had the inline 6 and V-6

Canadian models had the inline 6 and V-8

I have the car and truck 1960 accessory manual on CD rom, do you need anything from that manual?

[bpmcgee]

Is that a chevy or a GMC manual? Were there optional gauges? Since the instrument cluster wa different, I imagine there would be different option codes surrounding them.

[brown7373]

The GMC used Pontiac V8 engines sometime in the 50's...not sure which years but I think it was like 1956-1958, and I don't think it continued into the 60's.

[TJ's Chevy]

Originally Posted by bpmcgee

JB,

Actually you couldn't get the same options -- you couldn't for instance, spec a GMC with the V8 or a Chevy with the 305 V6. And since they sometimes adjusted the rear-end gearing to match the engine, it's possible they came with different gears. And the clutches won't interchange between those two. And the GMC had a hydraulic clutch actuator, which means the master cylinder is going to be dual instead of single.

That's what I want to catalog.

Before I actually owned a GMC I thought as you do -- now I'm seeing that they aren't as interchangable as I assumed, and I wonder if anyone's written down this stuff.

B

GMC and Chevy shared the same Inline 6 through the years. Both used the 230-250-292.

The v6 was a GMC only option.

Another super rare and neat thing about the GMC V6. All magnum models had the option for a factory 4 barrel setup rather than the 2 barrel.

[TJ's Chevy]

Originally Posted by 60-66

There have been several discussions about all the differences between GMC and Chevrolet. It would still be nice if there was a dedicated forum here for Restoration and preservation of original trucks. While I like modified trucks , the restoration or factory details discussions are LOST on this site. The only section we have here is one continual thread. That thread is very difficult now to find anything in without spending a lot of time going through every page. They made a special section for Panels and Suburbans in the last few years but still no restoration or preservation section. I personally know of MANY here that feel the same way.

Just met a guy with a 66 Chevy C20 that is BONE STOCK. Never even left the county! It was a glass repair truck. Has a 283/sm420. Original colors, stake bed, and 17.5 inch wheels. Wish I had gotten some pictures. He is the 3rd owner.

[60-66]

Originally Posted by TJ's Chevy

Just met a guy with a 66 Chevy C20 that is BONE STOCK. Never even left the county! It was a glass repair truck. Has a 283/sm420. Original colors, stake bed, and 17.5 inch wheels. Wish I had gotten some pictures. He is the 3rd owner.

Thats real nice TJ but what does that have to do with my comment ?

[TJ's Chevy]

Originally Posted by 60-66

Thats real nice TJ but what does that have to do with my comment ?

Guess it was my way of saying I feel the same way. lol

[bpmcgee]

Originally Posted by 60-66

There have been several discussions about all the differences between GMC and Chevrolet. It would still be nice if there was a dedicated forum here for Restoration and preservation of original trucks. While I like modified trucks , the restoration or factory details discussions are LOST on this site. The only section we have here is one continual thread. That thread is very difficult now to find anything in without spending a lot of time going through every page. They made a special section for Panels and Suburbans in the last few years but still no restoration or preservation section. I personally know of MANY here that feel the same way.

60-66,

I managed to find a GMC sales data book and purchase it. I already had one for Chevy, so when it arrives I should be able to compare them page-by-page to get an idea of options, etc.

I was considering starting a Google document page with the data side by side for comparison. Perhaps we could get such a thing pinned.

I also bought a parts interchange manual which claims to be GMC specific, which will be another good start at identifying what crosses over and how.

B

[60-66]

Originally Posted by bpmcgee

60-66,

I managed to find a GMC sales data book and purchase it. I already had one for Chevy, so when it arrives I should be able to compare them page-by-page to get an idea of options, etc.

I was considering starting a Google document page with the data side by side for comparison. Perhaps we could get such a thing pinned.

I also bought a parts interchange manual which claims to be GMC specific, which will be another good start at identifying what crosses over and how.

B

Theres so many differences, B ,that the books do not explain , paint , assembly, chassis, bolts, many options are specific to GMC only just to name a few. Certain plants used the same methods as Chevy for paint and assembly yet others were built much different in technique. This is just naming a few.

Heres our ONE LONELY thread for restoration http://67-72chevytrucks.com/vboard/s...d.php?t=488680 .This is a good thread but it covers every subject in no specific order. Then theres several other threads you have to search for. Remember though , much info you'll read, can be stated, but not backed up , best to get several opinions and do a lot of research as GMC is difficult to get facts on unless you document survivor trucks and find a ton of GMC books. One comment already in this thread about a " rare 4 barrel intake for GMC" , this needs to be seen , as the person that originated that comment "Saw one in a junkyard" . When I get time I will dig for more info on that.

What year Data book did you find ? I have the 1960 1965 and 1969 along with several different accessory books specific to GMC. I have all the Chevrolet Data books from 1957-1972 . GMC data books are very tough to find.

Im just over the boarder in Wisconsin , maybe Ill get to see your truck one of these days. Jon