| Re: 455 or 403 in my coach? [message #361978 is a reply to message #361614] |
Mon, 25 January 2021 08:11   |
JRWood
Messages: 2
Registered: January 2021
Location: Murray, Kentucky
Karma:
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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.
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