Re: [GMCnet] engine block ID info [message #278325] |
Sun, 24 May 2015 21:33 |
BobDunahugh
Messages: 2465 Registered: October 2010 Location: Cedar Rapids, IA
Karma: 11
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Mike. From what I found out about 11 years ago. When I went looking for a 403 just to have around if I ever needed any parts. The car 403 will work in the GMC. I've been looking into the cams that were used in the 403, and 455. As covered last week. The Distributor, carb, and water pump are different then the car 403. I've always been under the impression that the cam was also specific to the GMC. So I've been looking into this for both the 403, and 455. It's beginning to look like there are 2 cams that may have been used in the 455 car engine. That was used in the GMC. It's looking like the 1973, 225 HP engine that developed it's peak torque of 360 ft lbs @ 2600 RPM. Or the other 1973 car 455 cam that was rated at 250 HP, with it's peak torque of 375 ft lbs @ 2800 RPM. As for the 403 cam that came in the the GMC. I believe it's cam came from a 350 by it's profile. This may have been because of emission standards. When ever I have to work on my 78 GMC 403. I'm
going to be looking into installing the 455 cam as I see it now by it's profile. I talked to Dick Paterson on this last Thursday. And he is thinking the same thing.
Bob Dunahugh78 Royale
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Re: [GMCnet] engine block ID info [message #278329 is a reply to message #278325] |
Sun, 24 May 2015 22:03 |
<rallymaster
Messages: 361 Registered: May 2014
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Does all this mean that the cam from the KOBA 455 engine is a drop-in and
will work in the 403?
ronC
On Sun, 24 May 2015 21:33:59 -0500 Bob Dunahugh
writes
When ever I have to work on my 78 GMC 403. I'm
> going to be looking into installing the 455 cam as I see it now by
> it's profile. I talked to Dick Paterson on this last Thursday. And
> he is thinking the same thing.
===========================================================
On Sun, 24 May 2015 21:33:59 -0500 Bob Dunahugh
writes:
> Mike. From what I found out about 11 years ago. When I went looking
> for a 403 just to have around if I ever needed any parts. The car
> 403 will work in the GMC. I've been looking into the cams that were
> used in the 403, and 455. As covered last week. The Distributor,
> carb, and water pump are different then the car 403. I've always
> been under the impression that the cam was also specific to the GMC.
> So I've been looking into this for both the 403, and 455. It's
> beginning to look like there are 2 cams that may have been used in
> the 455 car engine. That was used in the GMC. It's looking like the
> 1973, 225 HP engine that developed it's peak torque of 360 ft lbs @
> 2600 RPM. Or the other 1973 car 455 cam that was rated at 250 HP,
> with it's peak torque of 375 ft lbs @ 2800 RPM. As for the 403
> cam that came in the the GMC. I believe it's cam came from a 350
> by it's profile. This may have been because of emission standards.
> When ever I have to work on my 78 GMC 403. I'm
> going to be looking into installing the 455 cam as I see it now by
> it's profile. I talked to Dick Paterson on this last Thursday. And
> he is thinking the same thing.
> Bob Dunahugh78 Royale
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
Ron & Linda Clark
North Plains, ORYGUN
78 Eleganza II
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Re: [GMCnet] engine block ID info [message #278373 is a reply to message #278325] |
Mon, 25 May 2015 11:48 |
<rallymaster
Messages: 361 Registered: May 2014
Karma: 2
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The KOBA engine was one that was designed by the team of Arch, Jim Bounds
and a company in Florida (?) Arch wanted an engine with the best possible
low-end torque, and he said he didn't care whether it even ran above 3100
RPM (or thereabouts). Might be some small inaccuracies in the preceding
statement, but that's the gist of the origin.
RonC
On Mon, 25 May 2015 01:04:05 -0500 Bob Dunahugh
writes:
> What's a KOBA 455? I was looking at cam profile's as listed below. I
> think it will work. But I need to check the cam base line of
> rotation as used in the 403. And some other specs.
> Bob Dunahugh78 Royale4 original Yenko'sAnd too many other collector
> car's to be in my right mined.
>
>
>
>
> Mike. From what I found out about 11 years ago. When I went looking
> for a 403 just to have around if I ever needed any parts. The car
> 403 will work in the GMC. I've been looking into the cams that were
> used in the 403, and 455. As covered last week. The Distributor,
> carb, and water pump are different then the car 403. I've always
> been under the impression that the cam was also specific to the GMC.
> So I've been looking into this for both the 403, and 455. It's
> beginning to look like there are 2 cams that may have been used in
> the 455 car engine. That was used in the GMC. It's looking like the
> 1973, 225 HP engine that developed it's peak torque of 360 ft lbs @
> 2600 RPM. Or the other 1973 car 455 cam that was rated at 250 HP,
> with it's peak torque of 375 ft lbs @ 2800 RPM. As for the 403
> cam that came in the the GMC. I believe it's cam came from a 350
> by it's profile. This may have been because of emission standards.
> When ever I have to work on my 78 GMC 403. I'm
> going to be looking into installing the 455 cam as I see it now by
> it's profile. I talked to Dick Paterson on this last Thursday. And
> he is thinking the same thing.
> Bob Dunahugh78 Royale
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
Ron & Linda Clark
North Plains, ORYGUN
78 Eleganza II
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Re: [GMCnet] engine block ID info [message #278479 is a reply to message #278431] |
Tue, 26 May 2015 22:51 |
Bob de Kruyff
Messages: 4260 Registered: January 2004 Location: Chandler, AZ
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Kingsley Coach wrote on Tue, 26 May 2015 08:10FWIW
The auto 403 will work in the GMC BUT don't forget to change the dome (aka
intake manifold) and the oil pan to the GMC version. There may be other
minor swaps but I can't recall them right now.
Mike in NS
On Tue, May 26, 2015 at 9:47 AM, Jim Galbavy wrote:
> Rob,
>
> No big deal. I've called Drew by many first names too.
>
> His flat tapit 455 has been in my GMC for 13 years and is
> still going strong. Now that our offical rally season is over
> here in Florida, I'll be doing maintaince on her and change all
> her fluids and such in the coming weeks.
>
> jim galbavy
> '73 x-CL ANNIE
> Lake Mary, FL
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--
Michael Beaton
1977 Kingsley 26-11
1977 Eleganza II 26-3
Antigonish, NS
Life is too short to hold a grudge; slash some tires and call it even !
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The 403 intake manifold is not specific to the GMC--they are all low profile. Also, the 403 for the GMC did not have a specific cam.
Bob de Kruyff
78 Eleganza
Chandler, AZ
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