| 455 to 403 coach swap issues? [message #325280] |
Sun, 22 October 2017 10:24  |
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Matt Colie
Messages: 8547
Registered: March 2007
Location: S.E. Michigan
Karma: 7
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At the lunch bunch yesterday Greg Breem mentioned that the engine in his 78 Buzkick-Royale is in trouble but he has access to a fully rebuilt 455 coach engine that he can get at a reasonable price. From what I remember looking at the 403 here, there are more than a few changes. I do have zero first hand experience with this swap.
Does anyone have better information if this is a realistic thing to expect to do and not end up with something that is a mess?
Greg is not a mechanic and would have to trust someone to do the job right.
Matt
Matt & Mary Colie - Chaumière -'73 Glacier 23 - Members GMCMI, GMCGL, GMCES
Electronically Controlled Quiet Engine Cooling Fan with OE Rear Drum Brakes with Applied Control Arms
SE Michigan - Near DTW - Twixt A2 and Detroit
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| Re: 455 to 403 coach swap issues? [message #325306 is a reply to message #325280] |
Sun, 22 October 2017 20:15  |
xplorid
Messages: 213
Registered: February 2012
Location: Boise
Karma: 0
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Tell Greg to make me an offer for the roller cam 403 in my garage in Boise. Just put it back up on the Swap Meet page a few days ago. I know a shop in Warren that could facilitate , and I am really anxious to get the engine out of my garage and running in someone's coach.
Jeff
in Toledo at the moment visiting my folks.
1974/94 GMCII by Explorer
Manny 6.5 TD Al radiator
1 ton front 4 bags back
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| Re: 455 to 403 coach swap issues? [message #325309 is a reply to message #325280] |
Mon, 23 October 2017 01:55 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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Not a whole lot to change. We did it on Roger Blacks coach at least 12 years ago (maybe longer). The biggest difference that I remember was the oil cooler lines are different. Also I believe the radiator hoses and some vacuum line routing were different. I'm working on a 403 right now trying to get it going. I haven't noticed much difference other than there is more room to get to things.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: 455 to 403 coach swap issues? [message #325319 is a reply to message #325280] |
Mon, 23 October 2017 09:06 |
JohnL455
Messages: 4447
Registered: October 2006
Location: Woodstock, IL
Karma: 12
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I think if the new engine has all the accessory brackets intact you will be miles ahead. IIRC it is different. Also are the exhaust pipes to mufflers different from BB to SB? I would think so. Waiting for answers.
John Lebetski
Woodstock, IL
77 Eleganza II
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| Re: 455 to 403 coach swap issues? [message #325320 is a reply to message #325319] |
Mon, 23 October 2017 09:23 |
Ken Burton
Messages: 10030
Registered: January 2004
Location: Hebron, Indiana
Karma: 10
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|I forgot about the exhaust but I do not remember us having a problem with them. I was not there the whole time so maybe Roger took care of that when I wasn't around.
Ken Burton - N9KB
76 Palm Beach
Hebron, Indiana
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| Re: [GMCnet] 455 to 403 coach swap issues? [message #325321 is a reply to message #325320] |
Mon, 23 October 2017 10:33 |
Kosier
Messages: 834
Registered: February 2008
Karma: 1
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If the exhaust pipe lacks clearance under the crossmember, just cut it and
add an inch. The 403 has a nicer mount for the alternator, but
because the head is now higher, it will probably touch the engine lid. I
just ground a little clearance where it touched. IIRC, there's two
pieces to the PS pump that don't touch now, but a longer bolt and a tubing
spacer took care of that. The increased torque means the
tires spin more easily, but the will still last a long time.
Gary Kosier
77PB w/500Cad
Newark, Ohio
--------------------------------------------------
From: "Ken Burton"
Sent: Monday, October 23, 2017 10:23 AM
To:
Subject: Re: [GMCnet] 455 to 403 coach swap issues?
> |I forgot about the exhaust but I do not remember us having a problem with
> them. I was not there the whole time so maybe Roger took care of that
> when
> I wasn't around.
> --
> Ken Burton - N9KB
> 76 Palm Beach
> Hebron, Indiana
>
> _______________________________________________
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| Re: 455 to 403 coach swap issues? [message #325322 is a reply to message #325320] |
Mon, 23 October 2017 10:58 |
Hal StClair
Messages: 971
Registered: March 2013
Location: Rio Rancho NM
Karma: -12
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You are right on the exhaust, the 455 is about 2" wider and the Y pipe will need to be modified. The exhaust manifolds are different between the two also. The 455's right side won't fit the 403.
Hal
"I enjoy talking to you. Your mind appeals to me. It resembles my own mind, except you happen to be insane."
1977 Royale 101348,
1977 Royale 101586, Diesel powered,
1974 Eagle Bus 45',w/slideout,
Rio Rancho, NM
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| Re: [GMCnet] 455 to 403 coach swap issues? [message #325341 is a reply to message #325340] |
Mon, 23 October 2017 16:10 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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The 403 engine oil cooler lines work on the 455. Not the other way around.
The oil filter adapter is surrounded by the exhaust manifold on the
passenger side. The a/c brackets and fuel lines in the vicinity of the
mechanical pump are different also. The late (77 & 78) coaches are hampered
by the front body mount support brackets. But, the 455 bolts up to the
cross member and transmission the same as the 403. Power steering pump is
the same, but spacers and brackets are different. So is the alternator
support brackets. Best to have all the brackets from a 455 to do the swap.
Watch for misalignment on the drive pulleys. Exhaust pipes will need some
work, too. Just my observations, yours might vary a bit.
Jim Hupy
Salem, Or
78 GMC ROYALE 403
On Oct 23, 2017 1:43 PM, "Charles Boyd" wrote:
> The oil filter adapter is different also. The one piece oil cooler lines
> should work.
> --
> C. Boyd
> 76 Crestmont
> East Tennessee
>
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