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Will a 455 crank fit into a 403

Posted By: jclockga On: 01-04-2008 @ 21:40:42         Reply | Edit
I have found several people to say they have knowlegde of a 455 crank being machined to fit a 403.Anyone have any ideas on this.Thanks

Posted By: Jonnyscotti On: 11-09-2006 @ 23:35:49     Reply | Top | Edit
I doubt it because the 455 is a Pontiac engine and the 403 is a an Oldsmobile engine.
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Posted By: littlegto16 On: 11-10-2006 @ 00:54:39     Reply | Top | Edit
Oldsmobile also had a 455,but I doubt it will work. You are probably thinking about a Pontiac 455 crank being machined to fit a Pontiac 400 block,which can be done. But by the time you buy the bearings that you need it is cheaper to buy an aftermarket crankshaft that is already made for that and doesn't need to be machined.

Posted By: miketransamkid On: 11-10-2006 @ 06:25:24     Reply | Top | Edit
I doubt the olds 455 crank will work in a 403. 403 has very limited options as to what you can do to it. The bottom end is already weaker than a 400 pontiac. I built up a 403 over the summer and it wsnt cheap but i was going for a stock appearing motor with bolt ons. But i had extensive machine work done to the heads (not cheap) and reused the rotating assembly. went with ARP main studs and rod bolts. Comp cams etc. My next build is definately gonna be a poncho motor. More options and somewhat cheaper. i know you can grab an eagle crank and H beam rods for like 1500 bucks.

thats just my 2 cents

Posted By: jclockga On: 11-11-2006 @ 02:15:35     Reply | Top | Edit
Thanks for the info.I just got the engine in today(403)And already blew a gasket after 18 miles.So I'm going with a 455.Found one running for 550.00 still in the car.Oh well another sleepless night in the shop.

Posted By: miketransamkid On: 11-12-2006 @ 10:08:25     Reply | Top | Edit
bummer, but how'd you blow the gasket?

Posted By: jclockga On: 11-12-2006 @ 22:53:50     Reply | Top | Edit
I havent figured that one out.The drivers side was blown between cylinders.And passenger was blown in water jacket.Already got a set of olds 350 3a heads,and a hotter camshaft.Already tore down,just waiting on the gaskets tommorow.But this engine sat for a couple of years,and has less than 75,000.Replace all the freeze plugs,and gaskets(except head)oh well we live and learn.

Posted By: miketransamkid On: 11-15-2006 @ 10:53:24     Reply | Top | Edit
the 3a heads arent gonna help yeah much. Thats still a smog head. im gonna post a link. I'm using a set of 7's with flat tops and can still use pump gas.

Posted By: miketransamkid On: 11-15-2006 @ 13:07:57     Reply | Top | Edit
heres a set of #5's on ebay

Posted By: lee73 On: 09-16-2007 @ 21:45:04     Reply | Top | Edit
An olds 455 crank will not fit into a 403 olds motor,no matter what you do.

Posted By: davidr On: 09-19-2007 @ 21:20:36     Reply | Top | Edit
Wow , you got a good deal on that 455 .

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Posted By: schroederfarley On: 11-17-2007 @ 17:57:04     Reply | Top | Edit
When and if you put the 455 in your car be aware that it may be wider than the 403. An Oldsmobile 455 is about an inch and a half to two inches wider at the top when compared to an Oldsmobile 350 so depending on what the 403 is based on (small or big block) you may have some fitting issues but I know the swap can be done. You will probably see a problem where the rear of the passenger side valve cover hits or comes extremely close to the airconditioning box if your car is so equipped. This makes it tough to get the valve cover off or get to the spark plugs. The box is fiberglass and can be modified to let the engine fit easier and still have the air work. It is not too difficult but it is time consuming. I have run across a similar issue when putting a 455 in a Buick Regal. It is definitely worth it. the oldsmobile will not take abuse above 5500 rpm without some lower end mods. Mondello's knows a lot about how to make an Olds live and can tell you what cam to use to get the performance you want. They specialize in Oldsmobile performance.

[ Edited on 11/17/2007 @ 18:09:33 ]

 << Previous Thread - Need info on boosting my '79 403 Olds Horses   Next Thread - Help decoding 1st gen Data Plate >> 

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