| Re: [GMCnet] 455 or 403 in my coach? [message #361979 is a reply to message #361978] |
Mon, 25 January 2021 11:27   |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma:
|
Senior Member |
|
|
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?
>
>
> [quote title=C Boyd wrote on Sun, 10 January 2021 12:14]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.
>
>
>
>
>
> _______________________________________________
> 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@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
http://list.gmcnet.org/mailman/listinfo/gmclist_list.gmcnet.org
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
|
|
|
|
GMCforum
Search
Help
Register
Login
Home
