| 403 to 455 upgrade [message #201928] |
Sun, 17 March 2013 13:19  |
Jon
Messages: 3
Registered: March 2013
Location: United States
Karma: 0
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I'm thinking about upgrading my stock 403 to the 455 in my 1978 Eleganza. I'm looking on craigslist and I'm able to find all sorts of 455 engines, obviously all GM. is there any configuration that I should be looking for, or will they all work? Also, does the 403 transaxle also mate with the 455, or do i need to pull a transaxle out of a tornado with the 455? Also, I have a shop to work in with almost anything I need to pull the engine, but how big of a task is this upgrade? any help would be appreciated.
Thanks
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| Re: 403 to 455 upgrade [message #201935 is a reply to message #201928] |
Sun, 17 March 2013 14:05  |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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Senior Member |
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Transmission is the same with both engines. Some external parts of the 455 are needed, because it is bigger than the 403 block. Try for a 455 from a Toronado. Add get all the external parts (intake manifold, exhaust manifolds, front motor mount. Have not done this, but these are a few of the differences. Also, the engine hatch cover has a different cut-out to help clear the carb air filter. Easy to add the difference in your current 403 hatch.
455 Olds engine, others are a more difficult transplant. f you really want to have fu, put the Caddy 500 in, as others have done. I have not owned a 403, but I'll told that there is not much to gain in doing the swap, unless perhaps, your 403 is bad.
Tom, MS II
plain jane 455 with Paterson Carb.
2012 Phoenix Cruiser model 2552
KA4CSG
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| Re: 403 to 455 upgrade [message #201946 is a reply to message #201928] |
Sun, 17 March 2013 15:24 |
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John Heslinga
Messages: 632
Registered: February 2011
Location: Edmonton, Alberta, Canada
Karma: 4
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Senior Member |
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Ive never experienced the 403 to 445 changeover, however there are differences between 455s installed in regular cars and the GMC.
Getting one from a Toronado will make more of them closer to the same. If you can find a parts donor GMC than you have a source for these differences.
Whether or not these things can transfer between your old 403 and the new 455 will have to be told by those with the experience.
- Oil pans on regular 455 are different than GMCMH
- Accessory brackets will also be different between reg 455 andGMCMH.
- Oil Filter adaptor are different.
- Intake manifold is different
- dipstick tube is different
- exhaust manifold is different
- oil fill cap and tube is different
- Starter is heavy Duty
- motor mounts are different
John and Cathie Heslinga
1974 Canyonlands 260
455, Manny tranny and 1 ton, 3:70 LS,
Red Seal Journeyman, DTE, BEd. MEd.
Edmonton, Alberta
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| Re: 403 to 455 upgrade [message #202004 is a reply to message #201946] |
Mon, 18 March 2013 06:57 |
tphipps
Messages: 3005
Registered: August 2004
Location: Spanish Fort, AL
Karma: 9
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Senior Member |
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Oil lines to radiator are different. 403 lines are off the oil filter adapter at a different angle, further away from the block.
Tom,
2012 Phoenix Cruiser model 2552
KA4CSG
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