455 or 403 in my coach?

boybach

boybach

Well-known member
Dec 9, 2020
1,036
198
63
Don't know for sure what engine is in my rig, did a quick search in the archive and unfortunately the "how to tell" link is dead but did come across
this

> Changeover began on Mar 1st 1977 with TZE167V101285 for GM finished
> coaches and TZE337V101287 for Transmodes.
>
>
>
> David Lee Greenberg

I just found out my VIN is TZE167V101295, so 10 units after the changeover to 403? Is this correct, there's definitely a 403 in my 77 Palm Beach?

I just registered the coach's VIN with the GMC Motorhome Registry and found out it was registered a few times before - originally in Tucson AZ then
Palmer Lake CO 2010 then Bakerfield CA 2014 (where the PO bought it and imported it to Canada)

Larry
--
Larry - Victoria BC -

1977 Palm Beach VIN TZE167V101295 - 39,000 original miles so far
 
"definitely" might be a bit of a stretch for a 44ish year old GMC!

But it sounds likely that it's a 403.

Rob
76 Royale Twin Beds, Dry Bath
Victoria, BC

>
> Don't know for sure what engine is in my rig, did a quick search in the archive and unfortunately the "how to tell" link is dead but did come across
> this
>
>> Changeover began on Mar 1st 1977 with TZE167V101285 for GM finished
>> coaches and TZE337V101287 for Transmodes.
>>
>>
>>
>> David Lee Greenberg
>
> I just found out my VIN is TZE167V101295, so 10 units after the changeover to 403? Is this correct, there's definitely a 403 in my 77 Palm Beach?
>
> I just registered the coach's VIN with the GMC Motorhome Registry and found out it was registered a few times before - originally in Tucson AZ then
> Palmer Lake CO 2010 then Bakerfield CA 2014 (where the PO bought it and imported it to Canada)
>
> Larry
> --
> Larry - Victoria BC -
>
> 1977 Palm Beach VIN TZE167V101295 - 39,000 original miles so far
 
Count the bolts on the rocker arm covers. If there are 10 per cover, it is
a 455. If there are 5, it's a 403..
Jim Hupy
Salem, Oregon

On Sun, Jan 10, 2021, 9:33 AM Rob via Gmclist
wrote:

> "definitely" might be a bit of a stretch for a 44ish year old GMC!
>
> But it sounds likely that it's a 403.
>
> Rob
> 76 Royale Twin Beds, Dry Bath
> Victoria, BC
>
> > On Jan 10, 2021, at 9:28 AM, twlldeen--- via Gmclist <

> >
> > Don't know for sure what engine is in my rig, did a quick search in the
> archive and unfortunately the "how to tell" link is dead but did come across
> > this
> >
> >> Changeover began on Mar 1st 1977 with TZE167V101285 for GM finished
> >> coaches and TZE337V101287 for Transmodes.
> >>
> >>
> >>
> >> David Lee Greenberg
> >
> > I just found out my VIN is TZE167V101295, so 10 units after the
> changeover to 403? Is this correct, there's definitely a 403 in my 77 Palm
> Beach?
> >
> > I just registered the coach's VIN with the GMC Motorhome Registry and
> found out it was registered a few times before - originally in Tucson AZ
> then
> > Palmer Lake CO 2010 then Bakerfield CA 2014 (where the PO bought it and
> imported it to Canada)
> >
> > Larry
> > --
> > Larry - Victoria BC -
> >
> > 1977 Palm Beach VIN TZE167V101295 - 39,000 original miles so far
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Sir, if it is factory OEM.... the steel fuel line from fuel pump to carburetor is routed to the left of the top radiator hose on a 403 and is routed
to the right of the radiator hose on a 455. A 403 will have an idle solenoid stop on the carburetor shaft and an extra vacuum tree on drivers side to
control the electric solenoid on the front of the drivers side head which is fed from a solenoid bolted on the front of the passenger head.. A 403
and a455 have the same number of detents for valve cover bolts but 455s are only tapped and drilled in every other one. On a 403 it is cast on the
side of the block in big numbers. A 455 is a big block and will have a sunk down intake to clear the floor. A 403 is a small block and does not need
the lower intake. A 403 has a more noticeable dog leg in the pass exhaust manifold to clear the oil filter and cooler adapter.

> Don't know for sure what engine is in my rig, did a quick search in the archive and unfortunately the "how to tell" link is dead but did come
> across this
>
> > Changeover began on Mar 1st 1977 with TZE167V101285 for GM finished
> > coaches and TZE337V101287 for Transmodes.
> >
> >
> >
> > David Lee Greenberg
>
> I just found out my VIN is TZE167V101295, so 10 units after the changeover to 403? Is this correct, there's definitely a 403 in my 77 Palm Beach?
>
> I just registered the coach's VIN with the GMC Motorhome Registry and found out it was registered a few times before - originally in Tucson AZ
> then Palmer Lake CO 2010 then Bakerfield CA 2014 (where the PO bought it and imported it to Canada)
>
> Larry

--
C. Boyd
76 Crestmont
East Tennessee
 
Thanks for the explanation but I haven't seen the coach I bought yet, thought it may be possible to determine from the VIN alone but maybe not eh?

Larry
--
Larry - Victoria BC -

1977 Palm Beach VIN TZE167V101295 - 39,000 original miles so far
 
Coach is 300 miles away and unable to see the engine - thanks anyway, I thought the VIN info would be enough but I guess not.

thanks

Larry
--
Larry - Victoria BC -

1977 Palm Beach VIN TZE167V101295 - 39,000 original miles so far
 
Do you have a pic of the engine?

> Thanks for the explanation but I haven't seen the coach I bought yet, thought it may be possible to determine from the VIN alone but maybe not
> eh?
>
> Larry

--
C. Boyd
76 Crestmont
East Tennessee
 
A 455 will have an engine identification decal on the rear of the pass valve cover. On a 403 it is a larger decal on the air filter.

> Do you have a pic of the engine?
>
>
>
>
>

> > Thanks for the explanation but I haven't seen the coach I bought yet, thought it may be possible to determine from the VIN alone but maybe not
> > eh?
> >
> > Larry

--
C. Boyd
76 Crestmont
East Tennessee
 
These 4 (confusing) entries in the registry database might help or not. ;-)

30 End Of 455 Engine 167v101284 Last 455ci engine
31 Begin 403 Engine 167v101281 Begin 403ci engine in
motorhome
32 Begin 403 Engine 337v101287 Begin 403ci engine in 23'
Transmode
33 Begin 403 Engine 367v101312 Royal 403ci Engine

The first two entries are all that matter to you since you have a GMC
finished coach. Since they overlap, they really do not help at all.

When you do find out for sure, I'll be very interested in knowing for the
registry notes.

bdub
admin, The GMC Motorhome Registry

-----Original Message-----
From: On Behalf Of twlldeen--- via Gmclist
Sent: Sunday, January 10, 2021 11:28 AM
Subject: [GMCnet] 455 or 403 in my coach?

Don't know for sure what engine is in my rig, did a quick search in the
archive and unfortunately the "how to tell" link is dead but did come across
this

> Changeover began on Mar 1st 1977 with TZE167V101285 for GM finished
> coaches and TZE337V101287 for Transmodes.
>
>
>
> David Lee Greenberg

I just found out my VIN is TZE167V101295, so 10 units after the changeover
to 403? Is this correct, there's definitely a 403 in my 77 Palm Beach?

I just registered the coach's VIN with the GMC Motorhome Registry and found
out it was registered a few times before - originally in Tucson AZ then
Palmer Lake CO 2010 then Bakerfield CA 2014 (where the PO bought it and
imported it to Canada)

Larry
--
Larry - Victoria BC -

1977 Palm Beach VIN TZE167V101295 - 39,000 original miles so far

_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
No I don't have any photos of the engine yet.

All I have are the pics posted in the thread "Anyone recognize this 77 Palm beach?"

thanks

Larry
--
Larry - Victoria BC -

1977 Palm Beach VIN TZE167V101295 - 39,000 miles
 
I would say only partially confusing. Construction
on the chassis that became 1284 with a 455 likely
started before that of 1281, 1282, and 1283 but
the 1284 was simply late to get its VIN assigned due
to slower completion than the latest and greatest!

Just my guess, of course.

D C "Mac" Macdonald
Amateur Radio K2GKK
Since 30 November '53
USAF and FAA, Retired
Member GMCMI & Classics
Oklahoma City, OK
"The Money Pit"
TZE166V101966
'76 ex-Palm Beach
k2gkk + hotmail dot com
________________________________
From: Gmclist on behalf of Billy Massey via Gmclist
Sent: Sunday, January 10, 2021 12:52
To: gmclist
Cc: Billy Massey
Subject: Re: [GMCnet] 455 or 403 in my coach?

These 4 (confusing) entries in the registry database might help or not. ;-)

30 End Of 455 Engine 167v101284 Last 455ci engine
31 Begin 403 Engine 167v101281 Begin 403ci engine in
motorhome
32 Begin 403 Engine 337v101287 Begin 403ci engine in 23'
Transmode
33 Begin 403 Engine 367v101312 Royal 403ci Engine

The first two entries are all that matter to you since you have a GMC
finished coach. Since they overlap, they really do not help at all.

When you do find out for sure, I'll be very interested in knowing for the
registry notes.

bdub
admin, The GMC Motorhome Registry
 
Looking more and more like it's gonna be a 403 under the hood.

thanks guys

Larry
--
Larry - Victoria BC -

1977 Palm Beach VIN TZE167V101295 - 39,000 miles
 
No matter what you hear, the 403 is a very good engine. You should be happy
no matter which engine you have.
Jim Hupy
Salem, Oregon

On Sun, Jan 10, 2021, 11:49 AM twlldeen--- via Gmclist <

> Looking more and more like it's gonna be a 403 under the hood.
>
> thanks guys
>
> Larry
> --
> Larry - Victoria BC -
>
> 1977 Palm Beach VIN TZE167V101295 - 39,000 miles
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>
 
Mr. Boyd, that is an excellent description of all the vacuum operated controls on my 403. It is very original looking. It is a recent purchase but
I have worked on a Royale also with a 403. My question; I would like to eliminate all of those devices that are unnecessary ie, thermal vacuum tree,
solenoids, hoses, etc. and just have the vacuum advance on the carb ported vacuum and appropriate port for trans modulator. In your opinion, are
those factory devices worth retaining? Would they likely even function properly at this age? Is it ok to eliminate them?

the left of the top radiator hose on a 403 and is routed to the right of the radiator hose on a 455. A 403 will have an idle solenoid stop on the
carburetor shaft and an extra vacuum tree on drivers side to control the electric solenoid on the front of the drivers side head which is fed from a
solenoid bolted on the front of the passenger head.. A 403 and a455 have the same number of detents for valve cover bolts but 403s are only tapped
and drilled in every other one. On a 403 it is cast on the side of the block in big numbers. A 455 is a big block and will have a sunk down intake
to clear the floor. A 403 is a small block and does not need the lower intake. A 403 has a more noticeable dog leg in the pass exhaust manifold to
clear the oil filter and cooler adapter.
 
Never rely on data as previous owners might converted.
Just look on the engine block and see if there is a casting that is hard to
miss that will show 403.
Also the valve cover bolts

On Mon, Jan 25, 2021 at 6:12 AM ihv8--- via Gmclist
wrote:

>
> Mr. Boyd, that is an excellent description of all the vacuum operated
> controls on my 403. It is very original looking. It is a recent purchase
> but
> I have worked on a Royale also with a 403. My question; I would like to
> eliminate all of those devices that are unnecessary ie, thermal vacuum tree,
> solenoids, hoses, etc. and just have the vacuum advance on the carb ported
> vacuum and appropriate port for trans modulator. In your opinion, are
> those factory devices worth retaining? Would they likely even function
> properly at this age? Is it ok to eliminate them?
>
>

> factory OEM.... the steel fuel line from fuel pump to carburetor is routed
> to
> the left of the top radiator hose on a 403 and is routed to the right of
> the radiator hose on a 455. A 403 will have an idle solenoid stop on the
> carburetor shaft and an extra vacuum tree on drivers side to control the
> electric solenoid on the front of the drivers side head which is fed from a
> solenoid bolted on the front of the passenger head.. A 403 and a455 have
> the same number of detents for valve cover bolts but 403s are only tapped
> and drilled in every other one. On a 403 it is cast on the side of the
> block in big numbers. A 455 is a big block and will have a sunk down intake
> to clear the floor. A 403 is a small block and does not need the lower
> intake. A 403 has a more noticeable dog leg in the pass exhaust manifold to
> clear the oil filter and cooler adapter.
>
>
>
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
>

--
Jim Kanomata
Applied/GMC, Newark,CA
jimk
http://www.gmcrvparts.com
1-800-752-7502
 
how many bolts holding a rocker cover on? Not spaces, bolts.

--johnny
--
Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
Braselton, Ga.
I forgive them all, save those who hurt the dogs. They must answer to me in hell
 
The 403 has 5 five bolts that hold each valve cover on the head.

The 455 has 10 ten bolts that hold the valve cover on>

J.R. Wright
GMC Great Laker MHC
GMCGL Tech Editor
GMC Eastern States Charter Member
GMCMI
78 GMC Buskirk 29.5’ Stretch
75 GMC Avion (Under Reconstruction)
Michigan

>
> how many bolts holding a rocker cover on? Not spaces, bolts.
>
>
> --johnny
> --
> Foolish Carriage, 76 26' Eleganza(?) with beaucoup mods and add - ons.
> Braselton, Ga.
> I forgive them all, save those who hurt the dogs. They must answer to me in hell
>
>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
> http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
 
Mr. Wood, the 403s I am familiar with belonged to friends that I was helping on. The 403 has larger pistons and a shorter stroke than the 455 and
calls for 12* initial timing and a carb with different idle circuits. It doesn’t want to idle like the longer stroke 455 engines at 650 rpm. The
idle circuit is the extra stuff we are talking about. I did try to figure out what it does and why but I still am not sure. If engine conditions are
at the right temp and all the different components are working correctly it controls the idle speed dashpot when the transmission is in Drive. I also
believe it has something to do with controlling the EGR valve which the motorhome does not have. I believe when you stop and transmission is in drive
the engine is held at a faster idle and when you put it in park it idles down so you can shut the engine off without dieseling. I know the parts are
not east to test and bout impossible to find. If the only reason is to stop dieseling when you shut engine off I believe you can accomplish that by
using the electric dashpot to be active and control idle while running and closing the butterflies completely when turned off as in other GM model
cars. I have also used the dashpot to activate with the A/C to increase idle speed with A/C on. As for advise on to keep and use or take it off?
Everybody I asked said take it off and turn the engine off while still in drive if dieseling is an issue. In my case the owner wanted it to work so
I did the best I could.. if you do decide to take it off, post the parts on the swap meet as I know of a few people that are looking for parts to
get theirs working. I’m sorry I’m not much help.

Mr. Boyd, that is an excellent description of all the vacuum operated controls on my 403. It is very original looking. It is a recent purchase but
I have worked on a Royale also with a 403. My question; I would like to eliminate all of those devices that are unnecessary ie, thermal vacuum tree,
solenoids, hoses, etc. and just have the vacuum advance on the carb ported vacuum and appropriate port for trans modulator. In your opinion, are
those factory devices worth retaining? Would they likely even function properly at this age? Is it ok to eliminate them?

> Sir, if it is factory OEM.... the steel fuel line from fuel pump to carburetor is routed to the left of the top radiator hose on a 403 and is
> routed to the right of the radiator hose on a 455. A 403 will have an idle solenoid stop on the carburetor shaft and an extra vacuum tree on
> drivers side to control the electric solenoid on the front of the drivers side head which is fed from a solenoid bolted on the front of the
> passenger head.. A 403 and a455 have the same number of detents for valve cover bolts but 403s are only tapped and drilled in every other one. On
> a 403 it is cast on the side of the block in big numbers. A 455 is a big block and will have a sunk down intake to clear the floor. A 403 is a
> small block and does not need the lower intake. A 403 has a more noticeable dog leg in the pass exhaust manifold to clear the oil filter and cooler
> adapter.

--
C. Boyd
76 Crestmont
East Tennessee
 
You must log in or register to reply here.
GMCMI Fall 2026 Rally
Applied GMC

Share this page

Share this page
Top Bottom
Back